UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

(Mark One)

For the fiscal year ended December 31, 20132015

Commission file number 1-13831001-13831

Quanta Services, Inc.

(Exact name of registrant as specified in its charter)

2800 Post Oak Boulevard, Suite 2600

Houston, Texas 77056

(Address of principal executive offices, including zip code)

(713) 629-7600

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

Title of Each Class

None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨x    No  þ¨

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ¨    No  þx

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ¨x    No  þ¨

Indicate by check mark whether the registrantRegistrant has submitted electronically and posted on its corporate web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrantRegistrant was required to submit and post such files).    Yes  þx    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of Registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to thisForm 10-K.  ¨

Indicate by check mark whether the registrantRegistrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  þx

As of June 30, 20132015 (the last business day of the Registrant’s most recently completed second fiscal quarter), the aggregate market value of the Common Stock of the Registrant held by non-affiliates of the Registrant, based on the last sale price of the Common Stock reported by the New York Stock Exchange on such date, was approximately $5.5$5.7 billion.

As of February 21, 2014,23, 2016, the number of outstanding shares of Common Stock of the Registrant was 213,353,417.152,907,166. As of the same date, 3,500,000 exchangeable shares of a Canadian subsidiary of the Registrant associated with one share of Series F Preferred Stock of the Registrant were outstanding, and 899,858449,929 exchangeable shares of a Canadian subsidiary of the Registrant associated with one share of Series G Preferred Stock of the Registrant were outstanding and an additional 2,926,113 exchangeable shares of certain other Canadian subsidiaries of the Registrant were outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant’s Definitive Proxy Statement for the 20142016 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.

QUANTA SERVICES, INC.

ANNUAL REPORT ON FORM 10-K

For the Year Ended December 31, 20132015

INDEX

PART I

General

Quanta Services, Inc. (Quanta) is a leading provider of specialty contracting services, offering infrastructure solutions primarily to the electric power and oil and gas industries in North Americathe United States, Canada and inAustralia and select other international markets. The services we provide include the design, installation, upgrade, repair and maintenance of infrastructure within each of the industries we serve, such as electric power transmission and distribution networks, substation facilities, renewable energy facilities, pipeline transmission and distribution systems and facilities, and infrastructure services for the offshore and inland water energy markets.

We also own fiber optic telecommunications infrastructure in select markets and license the right to use these point-to-point fiber optic telecommunications facilities to customers and have recently expandedreport our fiber optic service offerings to include lit network services.

Effective December 31, 2013, Quanta’s Natural Gas and Pipeline Infrastructure Services segment was renamed the Oil and Gas Infrastructure Services segment to better align with this segment’s service offerings and end-customer markets. No changes have been made to this segment’s financial results. Our results are reported under threetwo reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services and (3) Fiber Optic Licensing and Other.Services. This structure is generally focused on broad end-user markets for our services. Our consolidated revenues for the year ended December 31, 20132015 were approximately $6.52$7.57 billion, of which 69%65% was attributable to the Electric Power Infrastructure Services segment 29%and 35% to the Oil and Gas Infrastructure Services segment. As a result of the sale of our fiber optic licensing operations on August 4, 2015, we have presented our fiber optic licensing operations as discontinued operations and our ancillary telecommunications infrastructure services as part of our Electric Power Infrastructure Services segment and 2% tofor all periods presented in the Fiber Optic Licensing and Other segment.accompanying consolidated financial statements.

We have established a presence throughout the United States, Canada and Australia with a workforce of approximately 20,90024,500 employees as of December 31, 2013,2015, which enables us to quickly reliably and cost-effectivelyreliably serve a diversified customer base. We believe our reputation for responsiveness and performance, geographic reach, comprehensive service offering, safety leadership and financial strength have resulted in strong relationships with numerous customers, which include many of the leading companies in the industries we serve. Our ability to deploy services to customers throughout North Americathe United States, Canada and Australia as a result of our broad geographic presence and significant scope and scale of services is particularly important to our customers who operate networks that span multiple states or regions. We believe these same factors also position us to continue to take advantage of other international opportunities.

Representative customers include:

•    ConocoPhillips		•    SaskPower
•    Dominion Resources, Inc.		•    PPL EnergyPlusShell
•    DTE Energy Co.			•    Puget Sound Energy
•    Duke Energy Corporation		•    SaskPowerSpectra Energy
•    Electric Transmission Texas			•    Sharyland Utilities
•    Enbridge, Inc.		•    SNC LavalinSouthern California Edison Co.
•    Entergy Corporation		•    Suncor Energy Inc.
•    Enterprise Products Partners L.P.		•    Solar Project SolutionsTallgrass Energy

•    Exelon Corporation		•    South Texas Electric CooperativeTransCanada Corporation
•    Eversource Energy		•    United States Department of Defense
•    First Energy		•    Southern California Edison Co.Williams Companies Inc.
•    Georgia Power		•    Suncor Energy Inc.
•    Google Inc.		•    TransCanada Corporation
•    ITC Holdings Corp.		•    Xcel Energy Inc.

We were organized as a corporation in the state of Delaware in 1997, and since that time we have grown organically and have made strategic acquisitions, expanding our geographic presence and scope of services and developing new capabilities to meet our customers’ evolving needs.

We believe that our business strategies, along with our competitive and financial strengths, are key elements in differentiating us from our competition and position us to capitalize on future capital spending by our customers. We offer comprehensive and diverse solutions on a broad geographic scale and have a solid base of long-standing customer relationships in each of the industries we serve. We also have an experienced management team, both at the executive level and within our operating units, and various proprietary technologies that enhance our service offerings. Our strategies of expanding the portfolio of services we provide to our existing and potential customer base, increasing our geographic and technological capabilities, promoting best practices and cross-selling our services to our customers, as well as continuing to maintain our financial strength, place us in the position to capitalize on opportunities and trends in the industries we serve and to expand our operations globally. We continue to evaluate potential acquisitions of companies with strong management teams and good reputations and believe that our financial strength and experienced management team isare attractive to potential acquisition targets.

We and our customers continue to operate in a somewhatan uncertain business environment, and although there has been gradual improvement in the economy, our customers continue to face stringentheightened regulatory and environmental requirements as they implement projects to enhance and expand their infrastructure. Further, significant declines in oil prices and natural gas prices, since mid-2014 have reduced demand for some of our oil and gas infrastructure services, which could persist if market uncertainty continues due to an extended period of low oil and natural gas prices. These economic,regulatory and regulatoryother factors have negatively affected the timing of demand for our services in the past and may create uncertainty with regard to anticipated customer spending in future periods. We cannot definitively predict the timing or magnitude of the effect that industry trends may have on our business, particularly in the near-term. However, in recent periods we have experienced an increase in project awards and demand for our services, and many projects that had been negatively impacted by regulatory delays have overcome those challenges and commenced construction.

On December 3, 2012,April 29, 2015, we sold substantially allentered into a stock purchase agreement with Crown Castle International Corp. (Crown Castle) pursuant to which we agreed to sell our fiber optic licensing operations. The purchase agreement contained customary representations and warranties, covenants and indemnities. On August 4, 2015, we completed the sale for a purchase price of our domestic telecommunications infrastructure services operations and related subsidiaries. Accordingly,approximately $1 billion in cash, resulting in after-tax net proceeds of approximately $848 million. In the third quarter of 2015, we recognized a net of tax gain of approximately $171 million. We have presented the results of operations, financial position, and cash flows and disclosures of such telecommunications subsidiariesthe fiber optic licensing operations as discontinued operations for all applicable periods presented in this Annual Report on Form 10-K.our consolidated financial statements.

Reportable Segments

The following is an overview of the types of services provided by each of our reportable segments and certain of the long-term industry trends impacting each segment.segments.

Electric Power Infrastructure Services Segment

The Electric Power Infrastructure Services segment provides comprehensive network solutions to customers in the electric power industry. Services performed by the Electric Power Infrastructure Services segment generally include the design, installation, upgrade, repair and maintenance of electric power transmission and distribution infrastructure and substation facilities along with other engineering and technical services. This segment also provides emergency restoration services, including the repair of infrastructure damaged by inclement weather, the energized installation, maintenance and upgrade of electric power infrastructure utilizing unique bare hand and hot stick methods and our proprietary robotic arm technologies, and the installation of

“smart “smart grid” technologies on electric power networks. In addition, this segment designs, installs and maintains renewable energy generation facilities, consisting of solar, wind and certain types of natural gas generation facilities, and related switchyards and transmission infrastructure to transport power to demand centers.power. To a lesser extent, this segment provides services such as the construction of electric power generation facilities, the design, installation, maintenance and repair of commercial and industrial wiring, installation of traffic networks and the installation of cable and control systems for light rail lines.

Several industry trends provide opportunities for growth in demand for the services provided by the Electric Power Infrastructure Services segment, including the need to improve the reliability of aging powerlines and limited ancillary telecommunication infrastructure the expected long-term increase in demand for electric power and the incorporation of renewable generation and other new power generation sources into the North American power grid. We believe that we are the partner of choice for our electric power and renewable energy customers in need of broad infrastructure expertise, specialty equipment and workforce resources.

Demand for electricity in North America is expected to grow over the long term. North America’s electric power grid was not designed or constructed to serve today’s power needs and is not adequate to serve the power needs of the future. The electric power grid is aging, continues to deteriorate and lacks redundancy. The increasing demand for electricity, coupled with the aging infrastructure, has affected and will continue to affect reliability, requiring utilities to upgrade and expand their existing transmission and distribution systems. Current federal legislation also requires the power industry to meet federal reliability standards for its transmission and distribution systems. These system upgrades are resulting in increased spending and increased demand for our services in the near-term, and we expect this will continue over the long-term as well.

As demand for power grows, the need for new power generation facilities will grow as well. The future development of new traditional power generation facilities, as well as renewable energy sources such as solar, wind and certain types of natural gas generation facilities, will require new or expanded transmission infrastructure to transport power to demand centers. Renewable energy in particular often requires significant transmission infrastructure due to the remote location of renewable sources of energy. As a result, we anticipate that future development of new power generation will lead to increased demand over the long-term for our electric transmission design and construction services as well as our substation engineering and installation services.

The significant improvement in access to natural gas resources in unconventional shale formations in the United States and Canada, driven by technological advancements, has dramatically increased the near- and long-term supply of natural gas in North America. This increase in supply has also resulted in low natural gas prices for the past several years and the anticipation that natural gas prices will remain at attractive levels for the next several years. As a result, it is anticipated that the amount of electricity generated by natural gas powered plants will increase and the majority of new fossil fuel generation facilities built in North America for the foreseeable future will be fueled by natural gas. Further, the Environmental Protection Agency (EPA) has implemented certain emissions regulations that are resulting in the development of natural gas generation facilities to replace coal generation plants that are being retired in order to comply with the new regulations. These dynamics are anticipated to result in the need for new transmission and substation infrastructure to be built in North America to interconnect new natural gas fired generation facilities. It is also anticipated that modifications to and reengineering of existing transmission and substation infrastructure will be required when existing coal generation facilities are retired or shut down.

We consider renewable energy, including solar, wind and certain types of natural gas generation facilities, to be an ongoing opportunity for our engineering, project management and installation services. Concerns about greenhouse gas emissions, as well as the goal of reducing reliance on power generation from fossil fuels, are creating the need for more renewable energy sources. Renewable portfolio standards (RPS), which mandate that renewable energy constitute a specified percentage of a utility’s power generation by a specified date, exist in many states. We believe that our comprehensive services, industry knowledge and experience in the design,

installation and maintenance of renewable energy facilities will enable us to support our customers’ renewable energy efforts. Further, we have the financial strength to selectively provide financing solutions to customers in a modest but strategic way to help facilitate the development of renewable energy and other projects and also potentially create construction backlog for us.

Certain legislative and regulatory actions may also increase demand for our electric power infrastructure services. For example, in July 2011, the Federal Energy Regulatory Commission (FERC) issued Order No. 1000, which establishes transmission planning and cost allocation requirements for public utility transmission providers that are intended to facilitate multi-state electric transmission lines. The order requires planning for transmission to occur on both a local and regional basis and to take into account transmission needs driven by public policy requirements. It also provides rules for cost allocation across areas so that transmission costs are paid for by the beneficiaries of the infrastructure to be developed. The order also removes certain rights of first refusal from FERC-approved tariffs and agreements, which is intended to encourage a more competitive marketplace for transmission infrastructure development and allow development to occur more quickly. We believe that certain legislative and regulatory actions, such as FERC Order No. 1000, which was affirmed by FERC in May 2012, with the issuance of FERC Order No. 1000-A, could have a favorable impact on the development of transmission infrastructure over the medium- and long-term, and as a result, increase demand for our electric transmission services.

Oil and Gas Infrastructure Services Segment

The Oil and Gas Infrastructure Services segment provides comprehensive network solutions to customers involved in the development and transportation of natural gas, oil and other pipeline products. Services performed by the Oil and Gas Infrastructure Services segment generally include the design, installation, repair and maintenance of pipeline transmission and distribution systems, gathering systems, production systems, storage systems and compressor and pump stations, as well as related trenching, directional boring and automatic welding services. In addition, this segment’s services include pipeline protection, integrity testing, rehabilitation and replacement and fabrication of pipeline support systems and related structures and facilities. In 2013, we expanded intoWe also serve the offshore and inland water energy markets, primarily providing services to oil and gas exploration platforms, including mechanical installation (or “hook-ups”), electrical and instrumentation, pre-commissioning and commissioning, coatings, fabrication, pipeline construction, integrity services and marine asset repair. To a lesser extent, this segment designs, installs and maintains airport fueling systems as well as water and sewer infrastructure.

We see potential growth opportunities in this segment, primarily in the installation and maintenance of natural gas, natural gas byproducts and oil pipelines and related services for gathering systems and pipeline integrity. In particular, we believe the existing pipeline and gathering system infrastructure in North America is insufficient to support the increasing development of new sources of natural gas, oil and other liquids, such as the unconventional shale formations and Canadian oil sands. We anticipate it will take several years to build this infrastructure and believe this need will increase demand for our services over time. To diversify our mainline pipe service offerings, we have focused on opportunities to provide our infrastructure services for gathering systems and related facilities, particularly in the liquid-rich shale formations. We are increasing our presence in the areas of several shale formations through the establishment of local offices to better position us to pursue these opportunities.

Ongoing development of unconventional shale formations throughout North America has resulted in a significant increase in the continent’s natural gas supply as compared to several years ago. We believe the abundant natural gas supply, combined with lower gas prices, will stimulate demand for increased natural gas usage in the future. As one of the cleanest-burning fossil fuels for power generation, low-cost natural gas supports the U.S. goals of energy independence from foreign energy sources and a cleaner environment. The U.S. Energy Information Administration has stated that the number of natural gas-fired power plants built will increase significantly over the next two decades. Also, power generation from renewable energy sources

continues to increase and become a larger percentage of the overall power generation mix. We also believe natural gas will be the fuel of choice to provide backup power generation during times when renewable energy sources are not available. Additionally, the acceptance of nuclear energy as a means of meeting the growing demand for energy in North America remains uncertain. We believe these factors will result in increasing development of natural gas power generation to meet North America’s future energy needs, which will in turn result in increased demand for natural gas production and the need for additional pipeline infrastructure to connect natural gas supplies to demand centers, increasing the demand for our services.

The abundance, low price and long-term supply of North American natural gas is also resulting in efforts to develop liquefied natural gas (LNG) export facilities in the United States and Canada, which could provide pipeline and related facilities development opportunities for us. Natural gas prices in various international markets are significantly higher than North American natural gas prices, making the economics of exporting North American natural gas to international markets attractive. Although a number of LNG export facilities are in various stages of planning, permitting and development in the United States and Canada, and it is unlikely that all of them will be developed, we believe our comprehensive service offerings and broad geographic presence will enable us to competitively pursue these opportunities.

We also believe there are significant mainline pipeline opportunities in Australia driven by the production of coal seam gas for LNG export. A number of LNG export facilities are under construction and proposed for development, and pipelines and related infrastructure will be required to serve these facilities. In addition, unconventional shale plays in Australia are in the early stages of exploration and development and will require construction of significant gathering, mainline and related infrastructure. Through an acquisition in Australia in 2013, we further expanded our presence in this region and competitively positioned ourselves to meet Australia’s increasing infrastructure needs.

Additional pipeline infrastructure is also needed for the transportation of crude oil and other liquids from unconventional shale formations in the United States and Canada. Heavy crude oil from the Canadian oil sands is also being developed and requires pipelines to be built to take the product to refineries, many of which are in the coastal region along the Gulf of Mexico. Canadian oil sands and shale formations in certain parts of the U.S. and Canada contain significant reserves, and the economics of the production of these reserves depend on the price of oil. Oil prices are currently at a level that encourages the development of these oil reserves, which will require pipeline infrastructure to be built. We believe this need will increase demand for our services.

Other infrastructure, primarily midstream gathering systems, is also needed to support the development of unconventional shale formations. To diversify our transmission pipeline service offerings, we are also focusing on opportunities to provide our infrastructure services for gathering systems and related facilities, particularly in liquids-rich shale formations.

We believe there are meaningful opportunities for us to penetrate the offshore and inland water energy markets in providing various infrastructure design, installation and maintenance services primarily to the Gulf of Mexico region but also in select international markets. The offshore service opportunities we see are very similar to what we perform onshore in this segment, and several of our existing onshore customers who also have offshore assets have expressed interest in our ability to provide offshore services. Demand for offshore energy infrastructure services is similar to that on land, including the need for engineering, construction and maintenance services for new and existing offshore exploration and production platforms. In addition, the majority of the thousands of miles of marine based pipelines and related production facilities are approaching or are beyond the end of their useful lives. We see this as an opportunity to leverage our onshore pipeline integrity services and technology to the offshore market’s aging infrastructure. Further, we believe new regulations and the more stringent enforcement of existing regulations administered by the Bureau of Safety and Environmental Enforcement may create opportunities for offshore energy infrastructure construction, repair and replacement services.

As a result of recent significant pipeline incidents in the United States, federal and state regulatory agencies are implementing new pipeline safety rules and increasing enforcement activities. The U.S. Department of Transportation has implemented significant regulatory legislation through the Pipeline and Hazardous Materials Safety Administration relating to pipeline integrity requirements. Testing is expected to become more frequent, extensive and invasive, and more information will be available regarding the condition of the United States’ pipeline infrastructure. As a result, we anticipate a significant increase in spending allocated to pipeline integrity testing, rehabilitation and replacement services, and an increase in demand for the related services we provide over the coming years. We expect companies will increasingly seek out service providers that can provide a turnkey management solution. We believe we are one of the few companies in North America that offers a complete solution for pipeline companies and gas utilities as they focus on testing, rehabilitating and replacing their pipeline infrastructure.

Fiber Optic Licensing and Other Segment

The Fiber Optic Licensing and Other segment designs, procures, constructs, maintains and owns fiber optic telecommunications infrastructure in select markets and licenses the right to use these point-to-point fiber optic telecommunications facilities to our customers pursuant to licensing agreements, typically with terms from five to twenty-five years, inclusive of certain renewal options. Under these agreements, customers are provided the right to use a portion of the capacity of a fiber optic network (dark fiber), with the network owned and maintained by us. We are also expanding our fiber optic service offerings to provide lit services, with Quanta providing network management services to customers as well as owning the electronic equipment necessary to make the fiber optic network operational. We believe market opportunities exist for lit services that will enable us to leverage capacities of our dark fiber networks, as well as providing other attractive growth opportunities. The Fiber Optic Licensing and Other segment provides services to communication carriers as well as education, financial services, healthcare and other business enterprises with high bandwidth telecommunication needs. The telecommunication services primarily provided through this segment are subject to regulation by the Federal Communications Commission and certain state public utility commissions. The Fiber Optic Licensing and Other segment also provides various telecommunication infrastructure services on a limited and ancillary basis, primarily to our customers in the electric power industry.

The growth opportunities in our Fiber Optic Licensing and Other segment include the continued investment in our dark fiber networks to serve customers in new geographic regions as well as the expansion into lit services. We see opportunities for lit services for customers in multiple institutional sectors, including communications carriers as well as education, financial services, healthcare and other business enterprises. These growth opportunities exist in both the markets we currently serve, by expanding our existing network to add new customers, and expansion into new markets through the build-out of new networks. This expected growth will require significant capital expenditures to support our network expansion efforts.

Financial Information about Geographic Areas

We operate primarily in the United States; however, we derived $1.54 billion, $1.89 billion and $1.31 billion $861.5 million and $535.0 million of our revenues from foreign operations during the years ended December 31, 2013, 20122015, 2014 and 2011,2013, respectively. Of our foreign revenues, approximately 86%85%, 96%82% and 97%86% were earned in Canada during the years ended December 31, 2013, 20122015, 2014 and 2011,2013, respectively. In addition, we held property and equipment in the amount of $196.8$317.6 million and $151.9$372.9 million in foreign countries, primarily Canada, as of December 31, 20132015 and 2012.2014.

Our business, financial condition and results of operations in foreign countries may be adversely impacted by monetary and fiscal policies, currency fluctuations, regulatory requirements and other political, social and economic developments or instability. Refer to Item 1A.“Risk Factors”Factorsand Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operationsfor additional information.information and discussion regarding the impact of currency rate fluctuations.

Customers, Strategic Alliances and Preferred Provider Relationships

Our customers include electric power and oil and gas companies, as well as commercial, industrial and governmental entities. We have a large and diverse customer base, including many of the leading companies in

the industries we serve. Our 10 largest customers accounted for approximately 34%36% of our consolidated revenues during the year ended December 31, 2013.2015. Our largest customer accounted for approximately 9%8% of our consolidated revenues for the year ended December 31, 2013.2015.

Although we have a centralized marketing and business development strategy, management at each of our operating units is responsible for developing and maintaining successful long-term relationships with customers. Our operating unit management teams build upon existing customer relationships to secure additional projects and increase revenuerevenues from our current customer base. Many of these customer relationships originated decades ago and are maintained through a partnering approach towith account management that includes project evaluation and consulting, quality performance, performance measurement and direct customer contact. Additionally, operating unit management focuses on pursuing growth opportunities with prospective new customers. We encourage operating unit management to cross-sell services of our other operating units to their customers and to coordinate with our other operating units to pursue projects, especially those that are larger and more complicated. Our business development group supports the operating units’ activities by promoting and marketing our services for existing and prospective large national accounts, as well as projects that would require services from multiple operating units.

We are a preferred vendor tofor many of our customers. As a preferred vendor, we have met minimum standards for a specific category of service, maintained a high level of performance and agreed to certain payment terms and negotiated rates. We strive to maintain preferred vendor status as we believe it provides us an advantage in the award of future work for the applicable customer.

We believe thatMany of our strategic relationships with customers in the electric power and oil and gas industries will continue to result in future opportunities. Many of these relationships take the form of strategic alliance or long-term maintenance agreements. Strategic alliance agreements generally state an intention to work together over a period of time and/or on specific types of projects, and many provide us with preferential bidding procedures. Strategic alliances and long-term maintenance agreements are typically agreements for an initial term of approximately two to four years thatand may include renewal options to extend the initial term.

Backlog

Backlog is not a term recognized under United States generally accepted accounting principles;principles (US GAAP); however, it is a common measurement used in our industry. Our methodology for determining backlog may not be comparable to the methodologies used by other companies.

Our backlog represents the amount of consolidated revenuerevenues that we expect to realize from future work under construction contracts, long-term maintenance contracts and master service agreements (MSAs) and licensing agreements.. These estimates include revenues from the remaining portion of firm orders not yet completed and on which work has not yet begun, as well as revenues from change orders, renewal options, and funded and unfunded portions of government contracts to the extent that they are reasonably expected to occur. For purposes of calculating backlog, we include 100% of estimated revenues attributable to consolidated joint ventures and variable interest entities (VIEs). The following table presents our total backlog by reportable segment as of December 31, 20132015 and 2012,2014, along with an estimate of the backlog amounts expected to be realized within 12 months of each balance sheet date (in thousands):

Revenue estimates included in our backlog can be subject to change as a result of project accelerations, cancellations or delays due to various factors, including but not limited to commercial issues, regulatory requirements and adverse weather. These factors can also cause revenue amounts to be realized in periods and at levels different than originally projected. Generally, our customers are not contractually committed to specific volumes of services under our MSAs, and while we did not experience any material cancellations during the current periods, most of our contracts may be terminated, typically upon 30 to 90 daysdays’ notice, even if we are not in default under the contract. We determine the estimated amount of backlog for work under MSAs by using recurring historical trends inherent in current MSAs, factoring in seasonal demand and projected customer needs based upon ongoing communications with the customer. In addition, many of our MSAs as well as contracts for fiber optic licensing, are subject to renewal options. As of December 31, 20132015 and 2012,2014, MSAs accounted for approximately 31%45% and 34%39% of our estimated 12 month backlog and approximately 44%50% and 45%47% of total backlog. There can be no assurance as to our customers’ actual requirements or that our estimates are accurate.

Competition

The markets in which we operate are highly competitive. We compete with other contractors in most of the geographic markets in which we operate, and several of our competitors are large companies that have significant financial, technical and marketing resources. In addition, there are relatively few barriers to entry into some of the industries in which we operate and, as a result, any organization that has adequate financial resources and access to technical expertise may become a competitor. A significant portion of our revenues is currently derived from unit price or fixed price agreements, and price is often an important factor in the award of such agreements. Accordingly, we could be underbid by our competitors in an effort by them to procure such business. We believe that as demand for our services increases, customers often consider other factors in choosing a service provider, including technical expertise and experience, financial and operational resources, nationwide presence, industry reputation and dependability, which we expect to benefit larger contractors such as us. In addition, competition may lessen as industry resources, such as labor supplies, approach capacity. There can be no assurance, however, that our competitors will not develop the expertise, experience and resources to provide services that are superior in both price and quality to our services, or that we will be able to maintain or enhance our competitive position. We also face competition from the in-house service organizations of our existing or prospective customers, including electric power, oil and gas and engineering companies, which employ personnel who perform some of the same types of services as those provided by us. Although a significant portion of these services is currently outsourced by many of our customers, in particular services relating to larger energy transmission infrastructure projects, there can be no assurance that our existing or prospective customers will continue to outsource these services in the future.

Employees

As of December 31, 2013,2015, we had approximately 20,90024,500 employees, consisting of approximately 3,2004,200 salaried employees, including executive officers, professional and administrative staff, project managers and engineers, job superintendents and clerical personnel, and approximately 17,70020,300 hourly employees, the number of which fluctuates depending upon the number and size of the projects we undertakethat are ongoing and planned at any particular time. Approximately 58%55% of our hourly employees at December 31, 20132015 were covered by collective bargaining agreements, primarily with the International Brotherhood of Electrical Workers (IBEW), the Canadian Union Skilled Workers (CUSW), Australia Workers’ Union and the four pipeline construction trade unions administered by the Pipe Line Contractors Association (PLCA), which are the Laborers International Union of North America, International Brotherhood of Teamsters (Teamsters), United Association of Plumbers and Pipefitters and the International Union of Operating Engineers. These collective bargaining agreements require the payment of specified wages to our union employees, the observance of certain workplace rules and the payment of certain amounts to multi-employermultiemployer pension plans and employee benefit trusts rather than us sponsoring or administering the benefit programs provided on behalf of our employees. These collective bargaining agreements have varying terms and expiration dates. The majority of the collective bargaining agreements contain provisions that prohibit work stoppages or strikes, even during specified negotiation periods relating to agreement renewals, and provide for binding arbitration dispute resolution in the event of prolonged disagreement.

We provide health, welfare and benefit plans for employees who are not covered by collective bargaining agreements. We also have a 401(k) plan pursuant to which eligible employees who are not provided retirement

benefits through a collective bargaining agreement may make contributions through a payroll deduction. We make matching cash contributions of 100% of each employee’s contribution up to 3% of that employee’s salary and 50% of each employee’s contribution between 3% and 6% of such employee’s salary, up to the maximum amount permitted by law.

Our industry is experiencing a shortage of journeyman linemen in certain geographic areas. In response to the shortage and to attract qualified employees, we utilize various IBEWInternational Brotherhood of Electrical Workers (IBEW) and National Electrical Contractors Association (NECA) training programs and support the joint IBEW/NECA Apprenticeship Program which trains qualified electrical workers. Certain of our Canadian operations also support the CUSW’sCanadian Union Skilled Workers (CUSW)’s apprenticeship programs for training construction and maintenance electricians and powerline technicians. We have also established apprenticeship training programs approved by the U.S. Department of Labor for employees not subject to the IBEW/NECA Apprenticeship Program, as well as additional company-wide and project-specific employee training and educational programs.

We believe our relationships with our employees and union representatives are good.

Materials

Our customers typically supply most or all of the materials required for each job. However, for some of our contracts, we may procure all or part of the materials required. As we continue to expand our comprehensive engineering, procurement and construction offerings, (EPC), particularly associated with utility scale solar projects, the cost of materials may become a proportionately larger component of our consolidated cost of services. We purchase such materials from a variety of sources and do not anticipate experiencing any significant difficulties in procuring such materials.

Training, Quality Assurance and Safety

Performance of our services requires the use of equipment and exposure to conditions that can be dangerous.hazardous conditions. Although we are committed to a policy of operating safely and prudently, we have been and will continue to be subject to claims by employees, customers and third parties for property damage and personal injuries resulting from performance of our services.injury. Our operating units have established comprehensive safety programs, policies and procedures and regulations and requirerequiring that employees complete prescribed training and service programs prior to starting work. Our operating units performing more sophisticated and technical jobs which is in addition to thoseutilize, when applicable, training programs required, if applicable,provided by the IBEW/NECA Apprenticeship Program, the training programs sponsored by the four trade unions administered by the PLCA,Pipe Line Contractors Association (PLCA), the apprenticeship training programs sponsored by the CUSW or our equivalent programs. Under the IBEW/NECA Apprenticeship Program, all journeyman linemen are required to complete a minimum of 7,000 hours of on-the-job training, approximately 144 hours of classroom education and extensive testing and certification. Certain of our operating units have established apprenticeship training programs approved by the U.S. Department of Labor that prescribe equivalent training requirements for employees who are not otherwise subject to the requirements of the IBEW/NECA Apprenticeship Program. Similarly, the CUSW offers apprenticeship training for construction and maintenance electricians that requires five terms of 1,700 hours each, combining classroom and on-the-job training, as well as training for powerline technicians that also involves classroom and jobsite training over a four-year period. In addition, the Laborers International Union of North America, the International Brotherhood of Teamsters, the United Association of Plumbers and Pipefitters and the International Union of Operating Engineers have training programs specifically designed for developing and improving the skills of their members who work in the pipeline construction industry. Our operating units also benefit from sharingshare best practices regarding theirfor training and educational programs and comprehensive safety policiespolicies.

Additionally, we have implemented two enterprise-wide programs, an Automated External Defibrillator (AED) program, which provides AEDs to all of our crews, and regulations.a Flame Resistant Personal Protection Equipment (FR) program, which provides fire resistant clothing to employees that are potentially exposed to flames or

electrical arcs. During 2015, we also completed a training facility that includes electric power and pipeline infrastructure, which will help facilitate classroom and on-the-job training programs and allow us to train employees in a controlled environment without the challenges of limited structure access and live utility constraints.

Regulation

Our operations are subject to various federal, state, local and international laws and regulations including:

We believe that we have all the licenses required to conduct our operations and that we are in substantial compliance with applicable regulatory requirements. Our failure to comply with applicable regulations could result in substantial fines or revocation of our operating licenses, as well as give rise to termination or cancellation rights under our contracts or disqualify us from future bidding opportunities.

Environmental Matters and Climate Change Impacts

We are committed to the protection of the environment and train our employees to perform their duties accordingly. We are subject to numerous federal, state, local and international environmental laws and regulations governing our operations, including the handling, transportation and disposal of non-hazardous and hazardous substances and wastes, as well as emissions and discharges into the environment, including discharges to air, surface water, groundwater and soil. We also are subject to laws and regulations that impose liability and cleanup responsibility for releases of hazardous substances into the environment. Under certain of these laws and regulations, such liabilitiesliability can be imposed for cleanup of previously owned or operated properties or currently owned properties toat which hazardous substances or wastes were sentdischarged or disposed of by currenta former owner or former operations at our facilities,operator, regardless of whether we directly caused the contamination or violated any law at the time of discharge or disposal. The presence of contamination from such substances or wastes could also interfere with ongoing operations or adversely affect our ability to sell or lease the property or use our propertiesthe property as collateral for financing. In addition, we could be held liable for significant penalties and damages under certain environmental laws and regulations and also couldor be subject to a revocation of ourcertain licenses or permits, which could materially and adversely affect our business, results of operations and cash flows. Our contracts with our customers may also impose liabilitiesliability on us regardingfor environmental issues that arise through the performance of our services.

From time to time, we may incur costs and obligations for correcting environmental noncompliance matters and for remediation at or relating to certain of our properties. We believe that we are in substantial compliance with our environmental obligations to date and that any such obligations will not have a material adverse effect on our business or financial performance.

The potential physical impacts of climate change on our operations are highly uncertain. Climate change may result in, among other things, changes in rainfall patterns, storm patterns and intensitiesintensity and temperature levels. As discussed elsewhere in this Annual Report on Form 10-K, including in Item 1A.“Risk Factors”Factors, our operating results are significantly influenced by weather. Therefore, significant changes in historical weather

patterns could significantly impact our future operating results. For example, if climate change results in drier weather and more accommodating temperatures over a greater period of time in a given period, we may be able to increase our productivity, which could have a positive impact on our revenues and gross margins. In addition,

if climate change results in an increase in severe weather, such as hurricanes and ice storms, we could experience a greater amount of higher margin emergency restoration service work, which generally has a positive impact on our gross margins. Conversely, if climate change results in a greater amount of rainfall, snow, ice or other less accommodating weather conditions in a given period, we could experience reduced productivity, which could negatively impact our revenues and gross margins.

Risk Management and Insurance

We are insured for employer’s liability, general liability, auto liability and workers’ compensation claims. On August 1, 2013, we renewed our employer’s liability, general liability, auto liability and workers’ compensation policies for the 2013 - 2014 policy year. As a result of the renewal,Under these programs, the deductibles for general liability and auto liability increased from $5.0 million toare $10.0 million per occurrence, while the deductible for workers’ compensation remained atis $5.0 million per occurrence, and the deductible for employer’s liability remained atis $1.0 million per occurrence. Additionally, in connection with this renewal,We are generally self-insured for all claims that do not exceed the amount of letters of credit required by us to secure our obligations underthe applicable deductible. In connection with our casualty insurance programs, has increased. Between August 1, 2009 and July 31, 2013, all policy deductible levels were $5.0 million per occurrence, other than employer’s liability, which was subjectwe are required to a deductibleissue letters of $1.0 million.credit to secure our self-insured obligations. We also have employee health care benefit plans for most employees not subject to collective bargaining agreements, of which the primary plan is subject to a deductible of $375,000 per claimant per year.

Losses under all of these insurance programs are accrued based upon our estimate of the ultimate liability for claims reported and anour estimate of claims incurred but not reported, with assistance from third-party actuaries. These insurance liabilities are difficult to assess and estimate due to unknown factors, including the severity of an injury, the extent of damage, the determination of our liability in proportion to other parties and the number of incidents not reported. The accruals are based upon known facts and historical trends, and management believes such accruals are adequate. As of December 31, 2013 and 2012, the gross amount accrued for insurance claims totaled $161.8 million and $160.8 million, with $122.6 million and $120.2 million considered to be long term and included in other non-current liabilities. Related insurance recoveries/receivables as of December 31, 2013 and 2012 were $9.1 million and $22.2 million, of which $0.7 million and $2.3 million are included in prepaid expenses and other current assets and $8.4 million and $19.9 million are included in other assets, net.

We renew our insurance policies on an annual basis, and therefore deductibles and levels of insurance coverage may change in future periods. In addition, insurers may cancel our coverage or determine to exclude certain items from coverage, or we may elect not to obtain certain types or incremental levels of insurance if we believe that the cost to obtain such coverage exceeds the additional benefits obtained. In any such event, our overall risk exposure would increase, which could negatively affect our financial condition, results of operations financial condition and cash flows.

Seasonality and Cyclicality

Our revenues and results of operations can be subject to seasonal and other variations. These variations are influenced by weather, customer spending patterns, bidding seasons, receipt of required regulatory approvals, permits and rights of way, project timing and schedules, and holidays. Typically, our revenues are lowest inPlease read the first quartersection entitledSeasonality; Fluctuations of the year because cold, snowy or wet conditions can cause delays in projects. In addition, many of our customers develop their capital budgets for the coming year during the first quarter and do not begin infrastructure projects in a meaningful way until their capital budgets are finalized. Second quarter revenues are typically higher than those in the first quarter, as some projects begin, but continued cold and wet weather can often impact second quarter productivity. Third quarter revenues are typically the highest of the year, as a greater number of projects are underway and weather is more accommodating. Generally, revenues during the fourth quarter of the year are lower than the third quarter but higher than the second quarter. Many projects are completed in the fourth quarter, and revenues are often impacted positively by customers seeking to spend their capital budgets before the end of the year; however, the

holiday season and inclement weather can sometimes cause delays, reducing revenues and increasing costs. Any quarter may be positively or negatively affected by atypical weather patterns in a given part of the world, such as severe weather, excessive rainfall or warmer winter weather, making it difficult to predict these variations and their effect on particular projects quarter to quarter. The timing of project awards and unanticipated changes in project schedules as a result of delays or accelerations can also create variations in the level of operating activity from quarter to quarter.

These seasonal impacts are typical for our U.S. operations, but as our foreign operations continue to grow, we may see a lessening of this pattern impacting our quarterly revenues. For example, revenues in Canada are often higher in the first quarter as projects are accelerated so that work can be completed prior to the “break up”, as productivity is adversely affected by wet ground conditions during the warmer spring and summer months. Also, although revenues from Australia and other international operations have not been significant to our overall revenues to date, their seasonal patterns may differ from those in North America and may impact our seasonality more in the future.

Additionally, our industry can be highly cyclical. As a result, our volume of business may be adversely affected by declines or delays in new projects in various geographic regions, including the United States, Canada and Australia. Project schedules, particularly in connection with larger, longer-term projects, can also create fluctuations in the services provided, which may adversely affect us in a given period. The financial condition of our customers and their access to capital, variations in the margins of projects performed during any particular period, regional, national and global economic and market conditions, timing of acquisitions, the timing and magnitude of acquisition and integration costs associated with acquisitions, dispositions, fluctuations in our equity in earnings of unconsolidated affiliates and interest rate fluctuations are examples of items that may also materially affect quarterly results. Accordingly, our operating results in any particular period may not be indicative of the results that can be expected for any other period. You should read“Outlook” and“Understanding Margins”Results; Economic Conditions included in Item 7.“Management’s Discussion and Analysis of Financial Condition and Results of Operations”Operations for additional discussion of trends and challenges that may affect our financial condition, results of operations and cash flows..

Website Access and Other Information

Our website address is www.quantaservices.com.www.quantaservices.com. Interested parties may obtain free electronic copies of our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and any amendments to these reports through our website under the heading “InvestorsInvestors & Media/SEC Filings”Filings or through the website of the Securities and Exchange Commission (the SEC) at www.sec.gov.www.sec.gov. These reports are available on our website as soon as reasonably practicable after we electronically file them with, or furnish them to, the SEC. In addition, our Corporate Governance Guidelines, Code of Ethics and Business Conduct and the charters of each of our Audit Committee, Compensation Committee, Governance and Nominating Committee and Investment Committee are posted on our website under the heading “InvestorsInvestors & Media/Corporate Governance.” Governance.

We intend to disclose on our website any amendments or waivers to our Code of Ethics and Business Conduct that are required to be disclosed pursuant to Item 5.05 of Form 8-K. Free copies of these items may be obtained from our website. We will make available to any stockholder, without charge, copies of our Annual Report on Form 10-K as filed with the SEC. For copies of this or any other Quanta publication, stockholders may submit a request in writing to Quanta Services, Inc., Attn: Corporate Secretary, 2800 Post Oak Blvd., Suite 2600, Houston, TX 77056, or by phone at 713-629-7600.

Investors and others should note that we announce material financial information and make other public disclosures of information regarding Quanta through SEC filings, press releases, public conference calls, and our website. We also utilize social media to communicate this information, and it is possible that the information we post on social media could be deemed material. Accordingly, we encourage investors, the media and others interested in our company to follow Quanta, and review the information we post, on the social media channels listed on our website in theInvestors & Media section.

This Annual Report on Form 10-K, our website and our websitesocial media channels contain information provided by other sources that we believe are reliable. We cannot provide assurance that the information obtained from other sources is accurate or complete. No information on our website or our social media channels is incorporated by reference herein.

Our business is subject to a variety of risks and uncertainties, including, but not limited to, the risks and uncertainties described below. The matters described below are not the only risks and uncertainties facing our

company. Additional risks and uncertainties not known to us or not described below also may impair our business operations. If any of the following risks actually occur, our business, financial condition, results of operations and cash flows could be negatively affected, and we may not be able to achieve our goals or expectations. This Annual Report on Form 10-K also includes statements reflecting assumptions, expectations, projections, intentions or beliefs about future events that are intended as “forward-looking statements” under the Private Securities Litigation Reform Act of 1995 and should be read in conjunction with the section entitled“Uncertainty of Forward-Looking Statements and Information”Information included in Item 7.“Management’s Discussion and Analysis of Financial Condition and Results of Operations.”

Our operating results may vary significantly from quarter to quarter.

Our business can be highly cyclical and subject to seasonal and other variations that can result in significant differences in operating results from quarter to quarter. For example, we typically experience lower gross and operating margins during winter months due to lower demand for our services and more difficult operating conditions.conditions in the Northern hemisphere. Additionally, our quarterly results may be materially and/or adversely affected by:

Accordingly, our operating results in any particular quarter may not be indicative of the results that can be expected for any other quarter or for the entire year.

Negative economic and market conditions, including continued low oil and natural gas prices, may adversely impact our customers’ future spending as well as payment for our services and, as a result, our operations and growth.

The economy is still recovering from the recession in 2008 and 2009, and there is continuing uncertainty in the marketplace. Stagnant or declining economic conditions have adversely impacted the demand for our services in the past and resulted in the delay, reduction or cancellation of certain projects and may adversely affect us in the future. Additionally, many of our customers finance their projects through the incurrence of debt or the issuance of equity. A reduction in cash flow or the lack of availability of debt or equity financing may result in a reduction in our customers’ spending for our servicesIn addition, economic and may also impact the ability of our customers to pay amounts owed to us, which could have a material adverse effect on our operations and our ability to grow at historical levels.

Regulatory and environmental requirements and economicmarket conditions specifically affecting any of the industries we serve may lead to less demand for our services.

Because the vast majority of our revenue is derived from a few industries, regulatory and environmental requirements or a downturn in economic conditions affecting any of those industries wouldcould adversely affect our business, financial condition, results of operations. Customers in the industries we serve face heightened regulatory and environmental requirements and stringent permitting processes as they implement plans for their projects, which can result in delays, reductions and cancellations of some of their projects. Additionally, unfavorable economic conditions in any industry we serve could result in the delay, reduction or cancellation of projects by our customers, as well as cause our customers to outsource less work. These regulatory and economic factors have resulted in decreased demand for our services in the past, and they may continue to do so in the future, potentially impacting our operations and our ability to grow at historical levels.cash flows. A number of other factors, including financing conditions and potential bankruptcies in the industries we serve or a prolonged economic downturn or recession, could adversely affect our customers and their ability or willingness to fund capital expenditures in the future or pay for past services. Consolidation, competition, capital constraints or negative economic conditions in the electric power and oil and gas industries may also result in reduced spending by, or the loss of, one or more of our customers.

Our Oil and Gas Infrastructure Services segment is exposed to risks associated with the oil and gas industry. These risks, which are not subject to our control, include the volatility of natural gas and oil prices, the lack of

demand for natural gas and oil, including from power generation from natural gas, and a slowdown in the development or discovery of natural gas and/or oil reserves. Specifically, lower natural gas and oil prices have resulted in and could continue to result in decreased spending by some of our customers in our Oil and Gas Infrastructure Services segment. The increase in the global supply of oil and the significant increase in the North American supply of natural gas and oil due to ongoing development of unconventional shale formations has resulted in significant declines in natural gas and oil prices. Exploration and production companies, as well as some midstream companies, have significantly reduced capital spending and are expected to continue to operate with reduced budgets for the foreseeable future. A sustained period of lower prices, or the perceived risk of a sustained period of lower prices, may further reduce spending on exploration and production. As a result, our customers may also reduce capital spending on mainline pipe, gas gathering and compressor systems and other related infrastructure in the future, resulting in less demand for our services. If the profitability of our Oil and Gas Infrastructure Services segment were to continue to decline, our overall financial position, results of operations and cash flows could also be adversely affected. Additionally, if further declines in natural gas and oil prices further reduce investment in the development of resource plays and meaningfully reduce oil and natural gas production, our Electric Power Infrastructure Services segment could be negatively impacted. For example, the low price of oil has had an adverse impact on the Canadian economy, which has impacted demand for some of our electric power services in Canada.

Further, many of our customers finance their projects through the incurrence of debt or the issuance of equity. During depressed markets, such as the one facing the oil and natural gas industry currently, our customers may be unable to access capital markets or otherwise obtain financing for budgeted capital expenditures. A reduction in cash flow or the lack of availability of debt or equity financing for our customers could result in a reduction in our customers’ spending for our services and may also impact the ability of our customers to pay amounts owed to us, which could have a material adverse effect on our business, financial condition, results of operations, cash flows and our ability to grow.

Regulatory and environmental requirements affecting any of the industries we serve may lead to less demand for our services.

Because the vast majority of our revenue is derived from a few industries, the regulatory and environmental requirements affecting those industries have a material effect on our business, and increased regulatory and environmental requirements in those industries could adversely affect our business, financial condition, results of operations and cash flows. Customers in the industries we serve also face heightened regulatory and environmental requirements and stringent permitting processes that impact their projects, which can result in delays, reductions and cancellations of some of their projects. These regulatory factors have resulted in decreased demand for our services in the past, and they may continue to do so in the future, potentially impacting our business, financial condition, results of operations, cash flows and our ability to grow.

Project performance issues, including those caused by third parties, or certain contractual obligations may result in additional costs to us, reductions or delays in revenues or the payment of liquidated damages.

Many projects involve challenging engineering, permitting, procurement and construction phases that may occur over extended time periods, sometimes over several years. We may encounter difficulties as a result of delays in designs,design, engineering information or materials provided by the customer or a third party, delays or difficulties in equipment and material delivery, schedule changes, delays fromdue to our or our customers’ failure to timely obtain permits or rights-of-wayrights of way or meet other regulatory requirements or permitting conditions, weather-related delays and other factors, somemany of which are beyond our control, that can negatively impact our ability to complete the project and in accordance with the original delivery schedule. A failure by us to properly manage and invest in our equipment fleet could also negatively impact project performance and our financial condition, results of operations. operations and cash flows. Also, as we expand our scope of services for larger projects, we may face additional performance risks due to the larger and more complex work involved. The bidding processes for larger projects can also be longer and more complex, often taking six to nine months. Further, regulatory and permitting delays on larger projects tend to be more challenging and cause more uncertainty as to project timing.

In addition, we occasionally contract with third-party suppliers and subcontractors to assist us with the completion of contracts. Any delay or failure by suppliers or by subcontractors in the completion of their portion of the project may result in delays in the overall progress of the project or may cause us to incur additional costs, or both. We also may encounter project delays due to local opposition, which may include injunctive actions as well as public protests, to the siting of electric power, natural gas or oil transmission lines, solar or wind projects, or other facilities. Delays and additional costs may be substantial and, in some cases, we may be required to compensate the customer for such delays. We may not be able to recover all of such costs. In certain circumstances, we guarantee project completion by a scheduled acceptance date or achievement of certain acceptance and performance testing levels. Failure to meet any of our schedules or performance requirements could also result in additional costs or penalties, including liquidated

damages, and such amounts could exceed expected project profit. In extreme cases, the above-mentioned factors could cause project cancellations, and we may not be able to replace such projects with similar projects or at all. Such delays or cancellations may impact our reputation or relationships with customers, adversely affecting our ability to secure new contracts.

Our customers may change or delay various elements of a project before or after its commencement, or the design, engineering information, equipment or materials that are to be provided by the customer or other parties may be preliminarily deficient or delivered later than required by the project schedule, resulting in additional direct or indirect costs. Under these circumstances, we generally negotiate with the customer with respect to the amount of additional time required and the compensation to be paid to us. We are subject to the risk that we may be unable to obtain, through negotiation, arbitration, litigation or otherwise, adequate amounts to compensate us for the additional work or expenses incurred by us due to the above-mentioned delays and additional costs, including as a result of customer-requested change orders or failure by the customer to timely deliver items, such as engineering drawings or materials, required to be provided by the customer.meet its obligations. Litigation or arbitration of projectwith respect to payment terms under contracts and change orders or claims for compensation may beis generally lengthy and costly and may adversely affect our relationship with our customers or potential customers, and it is often difficult to predict when and for how much the claims will be resolved. A failure to obtain adequate extensions or compensation for these matters could require us to record a reduction to amounts of revenuerevenues and gross profit recognized in prior periods under the percentage-of-completion accounting method. Any such adjustments could be substantial. We may also be required to invest significant working capital to fund cost overruns while the resolution of claims is pending, which could adversely affect liquidityour business, financial condition, results of operations and financial results in any given period.cash flows.

Our business is labor intensive, and we may be unable to attract and retain qualified employees.

Our ability to maintain our productivity and profitability will beis limited by our ability to employ, train and retain the necessary skilled personnel necessary to meet our requirements.personnel. We cannot be certain that we willmay not be able to maintain an adequate skilled labor force necessary to operate efficiently and to support our growth strategy. For instance, we may experience shortages of qualified journeyman linemen, who are integral to the provision of transmission and distribution services under our Electric Power Infrastructure Services segment. The commencement of new, large-scale infrastructure projects or increased demand for infrastructure improvements, as well as the aging electric utility workforce, may also further reduce the pool of skilled workers available to us. In addition, in our Oil and Gas Infrastructure Services segment, there is limited availability of experienced supervisors and foremen that can oversee large mainline pipe projects. A shortage in the supply of these skilled personnel creates competitive hiring markets and may result in increased labor expenses. Additionally, if we are unable to hire employees with the requisite skills, we may also be forced to incur significant training expenses. Labor shortages or increased labor costs could impair our ability to maintain our business or grow our revenues or profitability.

Our use of fixed price contracts could adversely affect our business, andfinancial condition, results of operations.operations and cash flows.

We currently generate a portionsome of our revenues under fixed price contracts. We also expect to generate a greater portion of our revenues under this type of contract in the future as larger projects, such as electric power and pipeline transmission build-outs and utility-scale solar facilities, become a more significant aspect of our business. We assume

risks related to revenue, cost and costprofitability on fixed-priced contracts. Actual revenues and project costs can vary, sometimes substantially, from our original projections due to changes in a variety of factors including:

These variations,factors, along with other risks inherent in performing fixed price contracts may cause actual revenuerevenues and gross profits for a project to differ from thosewhat we originally estimated and could result in reduced profitability or losses on projects. Depending upon the size of a particular project, these variations from the estimated contract costs could have a significant impact on our operatingbusiness, financial condition, results for any fiscal period.of operations and cash flows. Additionally, we may be required to pay liquidated damages under certain of our contracts if we fail to meet schedule or performance requirements, which could harm our reputation and have a material adverse impact on our business, financial condition, results of operations and cash flows.

Our use of percentage-of-completion accounting could result in a reduction or elimination of previously reported profits.

As discussed in Item 7.“Management’s Discussion and Analysis of Financial Condition and Results of Operations — Critical Accounting Policies”Policies and in the notes to our consolidated financial statements included in Item 8. “Financial Statements and Supplementary Data”, a significant portionsome of our revenues are recognized using the percentage-of-completion method of accounting, utilizing the cost-to-cost method. This accounting method is generally accepted for fixed price contracts and is used because management considers expended costs to be the best available measure of progress on these contracts. This accounting method is generally accepted for fixed price contracts. The percentage-of-completion accounting practice we use results in our recognizingthe recognition of contract revenues and earnings ratably over the contract term in proportion to our incurrence of contract costs. The earnings or losses recognized on individual contracts are based on estimates of contract revenues, costs and profitability. Contract losses are recognized in full when losses are determined to be probable and can be reasonably estimable,estimated, and contract profit estimates are adjusted based on an ongoing reviewsreview of contract profitability. Further, a substantial portion of our contracts contain various cost and performance incentives. Penalties are recorded when known or finalized, which generally occurs during the latter stages of the contract. In addition, we record cost recovery claims when we believe recovery is probable and the amounts can be reasonably estimated. Actual collection of claims could differ from estimated amounts and could result in a reduction or elimination of previously recognized earnings. In certain circumstances, it is possible that such adjustments could be significant.

Our failure to adequately recover on claims brought by us against customers related to payment terms and costs could materially and adversely affect our financial position, results of operations and cash flows.

We have in the past brought, and may in the future bring, claims against our customers related to, among other things, the payment terms of our contracts and change orders relating to our contracts. These types of

claims occur due to, among other things, customer-caused delays or changes in project scope, both of which may result in additional cost, which may or may not be recovered until the claim is resolved. In some instances, these claims can be the subject of lengthy legal proceedings, and it is difficult to accurately predict when they will be fully resolved. A failure to promptly recover on these types of claims could have a negative impact on our financial condition, results of operations and cash flows.

Our operating results can be negatively affected by weather conditions.

We perform substantially all of our services in the outdoors. As a result, adverse weather conditions, such as rainfall or snow,snowfall, may affect our productivity in performing our services or may temporarily prevent us from performing services. The effect of weather delays on projects that are under fixed price arrangements may be greater if we are unable to adjust the project schedule for such delays. A reduction in our productivity in any given period or our inability to meet guaranteed schedules may adversely affect the profitability of our projects, and as a result, ourfinancial condition, results of operations.operations and cash flows.

We may be unsuccessful at generating internal growth.

Our ability to generate internal growth will be affected by, among other factors, our ability to:

In addition, our customers may cancel, delay or reduce the number or size of projects available to us for a variety of reasons, including capital constraints or inability to meet regulatory requirements. Many of the factors affecting our ability to generate internal growth may beare beyond our control, and we cannot be certain that our strategies for achieving internal growth will be successful.

Our business is highly competitive.competitive, and competitive pressures can affect our business, financial condition, results of operations and cash flows.

The specialty contracting business is served by numerous small, owner-operated private companies, some public companies and several large regional companies. In addition, relativelyRelatively few barriers prevent entry into some areas of our business. Asbusiness, and as a result any organization that has adequate financial resources and access to technical expertise may become one of our competitors. A substantial portion of our revenues is directly or indirectly dependent on winning new contracts. The timing of when project awards will be made is unpredictable and often involves complex and lengthy negotiations and bidding processes. These processes can be impacted by a wide variety of factors, including price, governmental approvals, financing contingencies, commodity prices, environmental conditions and overall market and economic conditions. We are currently experiencing the impacts of competitive pricing in certain of the markets we serve, such as the electric power market with respect to smaller scale transmission projects and distribution services. In addition, our bids may not be successful because of a client’s perception of our ability to perform the work or a client’s perception of technology advantages held by our competitors as well as other factors. Certain of our competitors may have lower overhead cost structures. Therefore, they may be able to provide their services at lower rates than we are able to provide.

In addition, some of our competitors have significant resources, including financial, technical and marketing resources. We cannot be certain that our competitors do not have or will not develop the expertise, experience and resources to provide services that are superior in both price and quality to our services. Similarly, we cannot be certain that we will be able to maintain or enhance our competitive position within the specialty contracting business or maintain our current customer basebase. Certain of our competitors may have lower overhead cost structures, and therefore may be able to provide the required services at current levels.lower rates than us. We also face competition from the in-house service organizations of our existing or prospective customers. Electric power and oil and gas service providers usually employ personnel who perform some of the same types of services we do,provide, and we cannot be certain that our existing or prospective customers will continue to outsource these services in the future.

Furthermore, a substantial portion of our revenues is directly or indirectly dependent on winning new contracts. The timing of when project awards will be made is unpredictable and often involves complex and lengthy negotiations and bidding processes. These processes can be impacted by a wide variety of factors, including price, governmental approvals, financing contingencies, commodity prices, environmental conditions and overall market and economic conditions. The competitive environment we operate in can also affect the timing of contract awards and the commencement or progress of work under awarded contracts. For example, based on rapidly changing competition dynamics, we have experienced, and may in the future experience, more competitive pricing in certain markets, such as the smaller scale transmission and distribution electric power market. Our bids also may not be successful due to, among other things, a potential customer’s perception of our ability to perform the work or the technological advantages held by our competitors. Additionally, changing competitive pressures can present difficulties in matching workforce size with available contract awards. As a result, the competitive environment we operate in could have a material adverse effect on our business, financial condition, results of operations and cash flows and could cause our results of operations and cash flows to fluctuate significantly from quarter to quarter.

Changes in government spending and legislative actions and initiatives relating to renewable energy and electric power may adversely affect demand for our services.

Demand for our services may not result from renewable energy initiatives. While many states currently have mandates in place that require specified percentages of power to be generated from renewable sources, states could reduce those mandates could be reduced or make themmade optional, which could reduce, delaythereby reducing, delaying or eliminateeliminating renewable energy development in the affected states.development. Additionally, renewable energy is generally more expensive to produce than traditional energy sources and may require additional power generation sources as backup. The locations of renewable energy projects are often remote and are not viable unless new or expanded transmission infrastructure to transport the power to demand centers is economically feasible. Furthermore, funding for renewable energy initiatives may not be available, whichis uncertain and has been further constrained as a result ofby tight credit markets. These factors have resulted in fewer renewable energy projects than anticipated and a delay in the construction of these projects and the related infrastructure, which has adversely affected the demand for our services. These factors could continue to result in delays or reductions in projects, which could further negatively impact our business.

The American Recovery and Reinvestment Act of 2009 (ARRA) provides for various stimulus programs, such as grants, loan guarantees, and tax incentives, relating to renewable energy, energy efficiency and electric power infrastructure. Some of these programs have expired, which may affect the economic feasibility of future projects. Additionally, while a significant amount of stimulus funds have been awarded, we cannot predict the timing and scope of any investments to be made under stimulus funding or whether stimulus funding will result in increased demand for our services. Investments for renewable energy and electric power infrastructure and telecommunications fiber deployment under ARRA programs may not occur, may be less than anticipated or may be delayed, any of which would negatively impact demand for our services.

Other current and potential legislative or regulatory initiatives may not result in increased demand for our services. Examples include legislation or regulations tothat require utilities to meet reliability standards, to ease siting and right-of-way issues for the construction of transmission lines, and to encourage installation of new electric power transmission and renewable energy generation facilities. It is not certain whether existing legislation will create sufficient incentives for new projects, when or if proposed legislative initiatives will be enacted or whether any potentially beneficial provisions will be included in the final legislation.

There are also a number of legislative and regulatory proposals tothat address greenhouse gas emissions, which are in various phases of discussion or implementation. The United States is also a party to a recent global, non-binding agreement that includes a voluntary plan to reduce greenhouse gas emissions over the next decade. The outcome of these pending federal and state actions to addressproposals and possible future legislative and regulatory proposals resulting from the global climate changeagreement could negatively affect the operations of our customers through costs of compliance or restraints on projects, which could reduce their demand for our services.

Our business is subject to operational hazards, and we are self-insured against certain potential liabilities.

Our business is subject to significant operational hazards due to the nature of services provided by our workforce and the conditions in which they operate. These hazards include those involving electricity, fires, natural gas explosions, mechanical failures and weather-related incidents. Our offshore operations are further subject to heightenedadditional risks, including blowouts, collisions, capsizings, vessels sinking or capsizing and damage from severe weather conditions. These hazards could cause personal injury and severe damage to property, equipment and the environment and could lead to suspension of operations and legal liabilities. If we are not fully insured or indemnified against such risksliabilities or a counterparty fails to meet its indemnification obligations to us, it could materially and adversely affect our business, financial condition, results of operations financial position and cash flows. Further, any such liabilities or accidents could adversely affect our safety record, maywhich could impact our ability to bid on certain work.

On August 1, 2013, we renewed ourWe are insured for employer’s liability, general liability, auto liability and workers’ compensation policies for the 2013 — 2014 policy year. As a resultclaims, but such insurance is subject to deductibles and limits and may be canceled or may not cover all of the renewal, theour losses. The deductibles under our insurance programs are $10.0 million per occurrence for general liability and auto liability increased from $5.0 million to $10.0 million per occurrence, while the deductible for workers’ compensation remained atinsurance programs, $5.0 million per occurrence and the deductible for employer’s liability remained atworkers’ compensation, and $1.0 million per occurrence. Additionally, in connection with this renewal, the amount of letters of credit required by us to secure our obligations under our casualty insurance programs has increased.occurrence for employer’s liability. We are primarilygenerally self-insured for all claims that do not exceed the amount of the applicable deductible. We also have employee healthcarehealth care benefit plans for most employees not subject to collective bargaining agreements, of which the primary plan is subject to a deductible of $375,000 per claimant per year. Our insurance policies include various coverage requirements, including the requirement to give appropriate notice. If we fail to comply with these requirements, our coverage could be denied.

Losses under all of these insurance programs are accrued based upon our estimates of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. These insurance liabilities are difficult to assess and estimate due to unknown factors, including the severity of an injury, the extent of damage, the determination of our liability in proportion to other parties and the number of incidents not reported. The accruals are based upon known facts and historical trends, and management believes such accruals are adequate. If we were to experience insurance claims or costs significantly above our estimates, our business, financial condition, results of operations and cash flows could be materially and adversely affected in a given period.affected.

During the ordinary course of our business, we may become subject to lawsuits or indemnity claims, which could materially and adversely affect our business and results of operations.

We have in the past been, and may in the future be, named as a defendant in lawsuits, claims and other legal proceedings duringthat arise in the ordinary course of our business. These actions may seek, among other things, compensation for alleged personal injury, workers’ compensation, employment discrimination and other employment-related damages, breach of contract, property damage, environmental liabilities, multiemployer pension plan withdrawal liabilities, punitive damages, and civil penalties or other losses or injunctive or declaratory relief. In addition, we generally indemnify our customers for claims related to the services we provide and actions we take under our contracts, with them, and, in some instances, we may be allocated risk through our contract terms for actions by our customers or other third parties. Because our services in certain instances may be integral to the operation and performance of our customers’ infrastructure, we have been and may become subject to lawsuits or claims for any failure of the systems that we work on, even if our services are not the cause of such failures, and we could be subject to civil and criminal liabilities to the extent that our services contributed to any property damage, personal injury or system failure. Insurance coverage may not be available or may be insufficient for these lawsuits, claims or legal proceedings. The outcome of any of

these lawsuits, claims or legal proceedings could result in significant costs and diversion of management’s attention to thefrom our business. Payments of significant amounts, even if reserved, could adversely affect our business, reputation, liquidity andfinancial condition, results of operations.operations and cash flows. For details on our existing litigation and claims, refer to Note 15 of the Notes to Consolidated Financial Statements in Item 8.“Financial Statements and Supplementary Data.”

Unavailability or cancellation of third party insurance coverage would increase our overall risk exposure as well as disrupt our operations.

We maintain insurance coverage from third party insurers as part of our overall risk management strategy and because some of our contracts require us to maintain specific insurance coverage limits. There can be no assurance that our insurance coverage will be sufficient or effective under all circumstances or against all claims and liabilities which we may be subject. Additionally, we renew our insurance policies on an annual basis, and therefore deductibles and levels of coverage may change in future periods. There can be no assurance that any of our existing insurance coverage will be renewed upon the expiration of the coverage period or that future coverage will be affordable at the required limits. In addition, our third party insurers could fail, suddenly cancel our coverage or otherwise be unable to provide us with adequate insurance coverage. If any of these events occur, our overall risk exposure would increase and our operations could be disrupted. For example, we have significant operations in California and other U.S. states which have an increased risk of wildfires. Should our insurers determine to exclude coverage for wildfires in the future, we could be exposed to significant liabilities and potentially a potential disruption of our California operations. If our risk exposure increases as a result of adverse changes in our insurance coverage, we could be subject to increased claims and liabilities that could negatively affect our business, financial condition, results of operations financial condition and cash flows.

Many of our contracts may be canceled or suspended on short notice or may not be renewed upon completion or expiration, and we may be unsuccessful in replacing our contracts in such events, which may adversely affect our financial condition, results of operations and financial condition.cash flows.

We could experience a decrease in our revenue,revenues, net income and liquidity if any of the following occur:

Many of our customers may cancel or suspend our contracts on short notice, typically 30 to 90 days, even if we are not in default under the contract. Certain of our customers assign work to us on a project-by-project basis under master service agreements. Under these agreements, our customers oftengenerally have no obligation to assign a specific amount of work to us. Our operations could decline significantly if the anticipated volume of work is not assigned to us, which will be more likely if customer spending decreases due to, for example, due to the slow recovery of the economy.unfavorable economic conditions. Many of our contracts, including our master service agreements, are opened to public bid at the expiration of their terms. There can be no assurance that we will be the successful bidder on our existing contracts that come up for re-bid.are subject to re-bid in the future.

The nature of our business exposes us to warranty claims, which may reduce our profitability.

Under our contracts with customers, we typically provide a warrantywarranties for the services and materials we provide, guaranteeing the work performed against, among other things, defects in workmanship and material.workmanship. The majority of our contracts have a warranty period of 12 months.to 18 months, although some are longer. As much of the work we perform is inspected by our customers for any defects in construction prior to acceptance of the project, the warranty claims that we have historically received have not been minimal.substantial. Additionally, materials used in construction are often provided by the customer or are warranted against defects fromby the supplier. However, certain projects such as utility-scale solar facilities, may have longer warranty periods and include facility performance warranties that may be broader than the warranties we generally provide. In these circumstances, if warranty claims occurred, it could require usoccur, we are generally required to re-perform the services and/or to repair or replace the warranted item, at a cost to us,our sole expense, and we could also result inbe responsible for other damages if we are

not able to adequately satisfy our warranty obligations.

In addition, we may be required under contractual arrangements with our customers to warrant any defects or failures in materials we provide that we purchase from third parties.provide. While we generally require the materials suppliers to provide us warranties that are consistent with those we provide to theour customers, if any of these suppliers default on their warranty obligations to us, we may incur costs to repair or replace the defective materials for which we are not reimbursed.materials. Costs incurred as a result of warranty claims could adversely affect our operatingbusiness, financial condition, results financial conditionof operations and cash flows.

The loss of one or a few customers could have a material adverse effect on us.

A few customers have in the past and may in the future account for a significant portion of our revenuerevenues in any one year or over a period of several consecutive years. Although we have long-standing relationships with many of our significant customers, our customers may unilaterally reduce or discontinue their contracts with us at any time. OurThe loss of business from a significant customer could have a material adverse effect on our business, financial condition, results of operations and cash flows.

Our profitability and financial condition may be adversely affected by risks associated with the oil and gas industry, such as price fluctuations and supply and demand for natural gas.

Certain of our services, in particular those under our Oil and Gas Infrastructure Services segment, are exposed to risks associated with the oil and gas industry. These risks, which are not subject to our control, include the volatility of natural gas and oil prices, the lack of demand for power generation from natural gas and a slowdown in the discovery or development of natural gas and/or oil reserves. Specifically, lower natural gas and oil prices generally result in decreased spending by our customers in our Oil and Gas Infrastructure Services segment. The significant increase in the North American supply of natural gas due to ongoing development of unconventional shale formations has resulted in low natural gas prices for the past several years. While higher natural gas and oil prices generally result in increased infrastructure spending by these customers, sustained high energy prices could be an impediment to economic growth and could result in reduced infrastructure spending by such customers. Higher prices could also decrease spending on natural gas fired electricity generation facilities and related infrastructure, an important component of our electric power infrastructure services business. Additionally, higher prices will likely reduce demand for power generation from natural gas, which could result in decreased demand for the expansion of North America’s natural gas pipeline infrastructure, and consequently result in less capital spending by these customers and less demand for our services.

Further, if the discovery or development of natural gas and/or oil reserves slowed or stopped, customers would likely reduce capital spending on mainline pipe, gas gathering and compressor systems and other related infrastructure, resulting in less demand for our services. If the profitability of our business under the Oil and Gas Infrastructure Services segment were to decline, our overall profitability, results of operations and cash flows could also be adversely affected.

Backlog may not be realized or may not result in profits.

Backlog is not a term recognized under United States generally accepted accounting principles;US GAAP; however, it is a common measurement used in our industry. Our methodology for determining backlog may not be comparable to the methodologies used by other companies. For a discussion of how we calculate backlog for our business, please seeBacklogin Item 1.Business.

Furthermore, backlog is difficult to determine with certainty. Customers often have no obligation under our contracts to assign or release work to us, and many contracts may be terminated on short notice. Reductions in backlog due to cancellation or reduction in scope of one or more contracts or projects by a customer or for other reasons could significantly reduce the revenuerevenues and profit we actually receive from contracts included in backlog. In the event of a project cancellation or reduction in scope, we may be reimbursed for certain costs but would not have a contractual right to the total revenues reflected in our backlog. The backlog we obtain in connection with any companies we acquire may not be as large as we believed orand may not result in the revenuerevenues or profits we expected.expected at the time of acquisition. In addition, projects that are delayed may remain in backlog for extended periods of time. All of these uncertainties are heightened by negative economic conditions and their impact on our

customers’ spending, as well as the effects of regulatory requirements and weather conditions. Consequently, we cannot assure that our estimates of backlog aremay not be accurate, or thatand we willmay not be able to realize our estimated backlog.

Our financial results are based upon estimates and assumptions that may differ from actual results.

In preparing our consolidated financial statements in conformity with accounting principles generally accepted in the United States,US GAAP, several estimates and assumptions are used by management in determiningto report the reported amounts of assets, liabilities, revenues and expenses recognized during the periods presented and disclosures ofto determine the contingent assets and liabilities known to exist as of the date of the financial statements. These estimates and assumptions must be madeare necessary because certain information that is used in the preparation of our financial statements is dependent on future events, cannot be calculated with a high degree of precision from available data available or is not capable of beingcannot be readily calculated based on generally accepted methodologies. In some cases, these estimates are particularly difficult to determine, and we must exercise significant judgment. Estimates are used primarily in our assessment of the allowance for doubtful accounts, valuation of inventory, useful lives of assets, fair value assumptions in analyzing goodwill, other intangibles and long-lived asset impairments, equity and other investments, loan receivables, purchase price allocations, liabilities for self-insured and other claims multi-employerand guarantees, multiemployer pension plan withdrawal liabilities, revenue recognition for construction contracts inclusive of contractual change orders and claims, revenue recognition for fiber optic licensing contracts, share-based compensation, operating results of reportable segments, provision (benefit) for income taxes and the calculation of uncertain tax positions. Actual results for all estimates could differ materially from the estimates and assumptions that we use, which could have a material adverse effect on our financial condition, results of operations and cash flows.

Our inability to successfully execute our acquisition strategy may have an adverse impact on our growth strategy.

Our business strategy includes expanding our presence in the industries we serve through strategic acquisitions of companies that complement or enhance our business. The number of acquisition targets that meet our criteria may be limited, and welimited. We may also face competition for acquisition opportunities. Some of our competitorsopportunities, and other potential acquirers may offer more favorable terms than us or have greater financial resources than we do.available for potential acquisitions. This competition may further limit our acquisition opportunities and our ability to grow through acquisitions or could raise the prices of acquisitions and make them less accretive, or possibly not accretive, to us. Acquisitions thatFailure to consummate future acquisitions could negatively affect our growth strategies. Additionally, the acquisitions we complete may pursue may also involve significant cash expenditures, the incurrence or assumption of debt or burdensome regulatory requirements. Anyrequirements, and any acquisition may ultimately have a negative impact on our business, financial condition, results of operations and cash flows. Any of these factors could inhibit our ability to consummate future acquisitions, which could negatively affect our growth strategies.

We may be unsuccessful at integrating businesses that either we have acquired or that we may acquire in the future, which may reduce the anticipated benefit from acquired businesses.

As a part of our business strategy, we have acquired, and may seek to acquire in the future, companies that complement or enhance our business. The success of this strategy will depend on our ability to realize the anticipated benefits from the acquired businesses, such as the expansion of our existing operations, elimination of redundant costs and capitalizing on cross-selling opportunities. To realize these benefits, however, we must successfully integrate the operations of the acquired businesses with our existing operations. Integrating our acquired companies involves a number of special risks, including:

We cannot be sure that we will be able to successfully integrate acquired companies with our existing operationscomplete the integration process without substantial costs, delays, disruptions or other operational or financial problems. Additionally, ifIf we do not implement proper overall business controls, our decentralized operating strategy could result in inconsistent operating and financial practices at the companies we acquire. Issues relatedAdditionally, failure to the integration process may result in adverse impact to our revenues, earnings and cash flows. Integrating oursuccessfully integrate acquired companies involves a number of special risks

thatbusinesses could have a negativeadversely impact on our business, financial condition, results of operations and cash flows, including:flows.

Our results of operations could be adversely affected as a result of impairments of goodwill, other intangible assets, long-lived assets or our investments.

When we acquire a business, we record an asset called “goodwill” equal to the excess amount we pay for the business, including liabilities assumed, over the fair value of the tangible and other intangible assets of the business we acquire. Goodwill and other intangible assets that have indefinite useful lives cannot be amortized,

but instead must be tested at least annually for impairment, while intangible assets that have finite useful lives are amortized over their useful lives. The accounting literature provides specific guidance for testing goodwill and other non-amortized intangible assets for impairment. Refer to Item 7.“Management’s Discussion and Analysis of Financial Condition and Results of Operations — Critical Accounting Policies”Policies for a detailed discussion. Management is required to make certain estimates and assumptions when allocating goodwill to reporting units and determining the fair value of a reporting unit’s net assets and liabilities, including, among other things, an assessment of market conditions, projected cash flows, investment rates, cost of capital and growth rates, which could significantly impact the reported value of goodwill and other intangible assets. Fair value is determined using a combination of the discounted cash flow, market multiple and market capitalization valuation approaches. Absent any impairment indicators, we perform our impairment tests annually during the fourth quarter. If there is a decrease in market capitalization declines below book value, in the future, this may be considered an impairment indicator.

As part of our 2015 annual test for goodwill impairment, we recorded a non-cash impairment charge of $39.8 million related to goodwill and $12.1 million related to customer relationships, trade names and non-compete agreement intangible assets. The extended low commodity price environment has significantly impacted certain reporting units within our Oil and Gas Infrastructure Services Division. Specifically, lower forecasted oil and gas services revenues for our Gulf of Mexico operations and certain operations in Australia resulted in impairments of goodwill and intangible assets. Any future impairments, including impairments of goodwill, intangible assets or investments, could have a material adverse effect on our financial condition and results of operations for the period in which the impairment is recognized.

During the fourth quarter of 2015, in conjunction with our annual test for goodwill impairment, we also recorded a property and equipment impairment of $6.6 million related to certain international renewable energy services operations based on the estimated future undiscounted cash flows associated with the asset group as compared to the carrying value before the impairment. Future events and unanticipated changes to assumptions could require additional provisions for impairment in future periods.

In addition, we enter into various types of investment arrangements in the normal course of business, each having unique terms and conditions. These investments may include equity interests we hold in business entities, including general or limited partnerships, contractual joint ventures or other forms of equity or profit participation. These investments may also include our participation in different finance structures such as the extension of loans to project specific entities, the acquisition of convertible notes issued by project specific entities or other strategic financing arrangements. Our equity method investments are carried at original cost and are included in other assets, net in our consolidated balance sheet and are adjusted for our proportionate share of the investees’ income, losses and distributions. Equity investments are reviewed for impairment by assessing whether anythere has been a decline in the fair value of the investment below the carrying value and whether that decline is considered to be other than temporary. In making this determination, factors such as the ability to recover the carrying amount of the investment and the inability of the investee to sustain future earnings capacity are evaluated in determining whether an impairment has occurred and should be recognized.

Any future impairments, including impairments of goodwill, intangible assets or investments, could have a material adverse effect on our results of operations for the period in which the impairment is recognized.

New federal or state telecommunications regulations, or changes in, or interpretations of, existing regulations, could adversely affect our Fiber Optic Licensing and Other segment.

Many of our Fiber Optic Licensing and Other segment customers benefit from the Universal Service“E-rate” program, which was established by Congress in the 1996 Telecommunications Act and is administered by the Universal Service Administrative Company (USAC) under the oversight of the Federal Communications Commission (FCC). Under the E-rate program, schools, libraries and certain healthcare facilities may receive subsidies for certain approved telecommunications services, internet access and internal connections. From time to time, bills have been introduced in Congress that would eliminate or curtail the E-rate program. Passage of such actions by the FCC or USAC to further limit E-rate subsidies could decrease the demand by certain customers for the services offered by our Fiber Optic Licensing and Other segment.

The licensing services we provide through our Fiber Optic Licensing and Other segment are subject to regulation by the FCC, to the extent that they are interstate telecommunications services, and by state regulatory agencies, when wholly within a particular state. To remain eligible to provide services under the E-rate program, we must maintain telecommunications authorizations in every state where we operate, and we must obtain such authorizations in any new state where we plan to operate. Changes in federal or state regulations could reduce the profitability of our Fiber Optic Licensing and Other segment, and delays in obtaining new authorizations could inhibit our ability to grow our Fiber Optic Licensing and Other segment in new geographic areas. We could be subject to fines if the FCC or a state regulatory agency were to determine that any of our activities or positions are not in compliance with certain regulations. If the profitability of our Fiber Optic Licensing and Other segment were to decline, or if the business of this segment were to become subject to fines, our overall results of operations and cash flows could also be adversely affected.

Our fiber optic services are capital intensive, require substantial investments, may expose us to industry specific risks and may have returns on investments that are less than expected.

Our fiber optic licensing business requires substantial amounts of capital investment to build out new fiber networks. In 2014, our proposed capital expenditures for our fiber optic licensing business are approximately $50 million to $60 million, $38.8 million of which is related to committed licensing arrangements as of December 31, 2013. Although we generally do not commit capital to new networks until we have a committed license arrangement in place with at least one customer, we may not be able to recoup our initial investment in the network, and we may not realize a return on the capital investment for an extended period of time. Furthermore, the amount of capital that we invest in our fiber optic network may exceed planned expenditures as a result of various factors, including difficulty in obtaining permits or rights of way or unexpected increases in costs due to labor, materials or project productivity, which would result in a decrease in the returns on our capital investments if licensing fees for the network were committed and could not be renegotiated. New or developing technologies or significant competition in any of our markets could also negatively impact our fiber optic licensing business. Any of these events could adversely affect our results of operations or result in an impairment of our fiber optic network.

Our expansion into the lit services market exposes us to additional risks, as we will be providing access to the fiber network that we own, as well as providing networking equipment and assuming responsibility for network management and service quality. These risks include, but are not limited to, those related to our ability to secure customers for our network in a competitive environment, and the ability to obtain additional capacity in the event of increased demand; network failures and service interruptions, including those outside of our control when we use dark fiber networks or circuits that we do not own or operate, which could expose us to customer liability or require expensive modifications; our ability to obtain agreements with building owners and managers to provide us with access to serve customers in multi-tenant facilities; our ability to obtain or construct additional building laterals to connect new buildings to our network; compliance with laws and regulations applicable to Internet service providers; Internet connectivity at both public and private interconnection points with network providers; relationships and agreements with carrier neutral data center operators and incumbent local exchange carriers; and security breaches and unauthorized access to our systems.

We extend credit to customers for purchases of our services and may enter into longer-term deferred payment arrangements or provide other financing or investment arrangements with certain of our customers, which subjects us to potential credit or investment risk that could, if realized, adversely affect our financial condition, results of operations financial condition and cash flows.

We grant credit, generally without collateral, to our customers, which include electric power utilities, oil and gas companies, governmental entities, general contractors, and builders, owners and managers of renewable energy facilities and commercial and industrial properties located primarily in the United States, Canada and Australia. We may also agree to allow our customers to defer payment on projects until certain milestones have been met or until the projects are substantially completed, and customers typically withhold some portion of amounts due to us as retainage. In addition, we may provide other forms of financing to our customers or make investments in our customers’ projects, typically in situations where we also provide services in connection with

the projects. Our payment arrangements with our customers subject us to potential credit risk related to changes in business and economic factors affecting our customers, including material changes in our customers’ revenues or cash flows. These changes may also reduce the value of any financing or equity investment arrangements we have with our customers. Many of our customers have been negatively impacted by uncertain economic conditions in recent years, and some may experience financial difficulties (including bankruptcies) that could impact our ability to collect amounts owed to us or impair the value of our investments in them.

If we are unable to collect amounts owed to us, our cash flows would be reduced and we could experience losses if the uncollectiblethose amounts exceeded current allowances. We would also recognize losses with respect to any investments that are impaired as a result of our customers’ financial difficulties. The risk of loss may increase for projects where we provide services and make a financing or equity investment. Losses experienced could materially and adversely affect our financial condition, results of operations and cash flows. The risks of collectability and impairment losses may increase for projects where we provide services as well as make a financing or equity investment.

The loss of key personnel could disrupt our business.

We depend on the continued efforts of our executive officers and on senior management, including the management at each of our operating units, including the businesses we acquire.units. Although we typically enter into employment agreements with terms of one to three years with our executive officers and certain other key employees, we cannot be certain that any individual will continue in such capacity for any particular period of time or that key employees of our future acquisition targets will be willing to enter into such agreements. The loss of key personnel, or the inability to hire and retain qualified employees, could negatively impact our ability to manage our business. We do not carry key-person life insurance on any of our employees.

We may be required to contribute cash to meet our underfunded obligations in certain multi-employermultiemployer pension plans.

Our collective bargaining agreements generally require us to participate with other companies in multi-employermultiemployer pension plans. To the extent those plans are underfunded, the Employee Retirement Income Security Act of 1974, as amended by the Multi-EmployerMultiemployer Pension Plan Amendments Act of 1980, may subject us to substantial liabilities under those plans if we withdraw from them or they are terminated or experience a mass withdrawal. For example, we are involved in the fourth quarter of 2011, we recognized a $32.6 million liability when certain ofseveral litigation matters associated with our subsidiaries withdrewwithdrawal from the Central States, Southeast and Southwest Areas Pension Plan (the Central States Plan). The amountultimate liability associated with these matters will depend on various factors, including interpretations of this liability is estimated based on information receivedthe terms of the collective bargaining agreements under which the subsidiaries participated and whether exemptions from the multi-employer plan in 2011, although the plan has asserted that additional amounts are due. The actual amount assessed by the plan for the withdrawal and the amount that we ultimately pay for the withdrawal liability mayapplicable to construction industry employers will be materially different than the amount currently recorded. Additionally,available. For additional information on October 9, 2013, we acquired a company that experienced a complete withdrawal from the Central States Plan prior to the date of our acquisition. Central States issued a notice and demand to the acquired company for a withdrawal liability and the acquired company, and now Quanta, has taken steps to challenge the amountmatters, please seeCollective Bargaining Agreements in Note 15 of the assessment by the Central States Plan.Notes to Consolidated Financial Statements in Item 8.Financial Statements and Supplementary Data.

In addition, the Pension Protection Act of 2006 added special funding and operational rules generally applicable to plan years beginning after 2007 for multi-employermultiemployer plans that are classified as “endangered,” “seriously endangered,” or “critical” status. Plans in these classifications must adopt measures to improve their funded status through a funding improvement or rehabilitation plan, which may require additional contributions from employers (which may take the form of a surcharge on benefit contributions) and/or modifications to retiree benefits. A number of multi-employermultiemployer plans to which we contribute or may contribute in the future are in “endangered,” “seriously endangered” or “critical” status. The amount of additional funds we may be obligated to contribute to these plans in the future cannot be estimated, as such amounts will likely be based on future work that requires the specific use of union employees covered by these plans, and the amount of that future work and the number of employees that may be affected cannot reasonably be estimated. Our performance of a significant amount of future services in areas that require us to utilize unionized employees covered by these affected plans, or a deterioration in the funding status of any of the plans to which our operating units contribute, could require significant additional contributions, which could detrimentally affect our financial condition, results of operations financial condition orand cash flows if we are not able to adequately mitigate these costs.

Our unionized workforce and related obligations could adversely affect our operations.

As of December 31, 2013,2015, approximately 58%55% of our hourly employees were covered by collective bargaining agreements. Although the majority of the collective bargaining agreements prohibit strikes and work stoppages, certain of our unionized employees participated in a strike and work stoppage during January 2012, and we cannot be certain that strikes or work stoppages will not occur in the future. Strikes or work stoppages can adversely impact our relationships with our customers and could cause us to lose business and decrease our revenue.

Our ability to complete future acquisitions could be adversely affected because of our union status for a variety of reasons. For instance, our union agreements may be incompatible with the union agreements of a business we want to acquire, and some businesses may not want to become affiliated with a union-based company. Additionally, we may increase our exposure to withdrawal liabilities for underfunded multi-employermultiemployer pension plans to which an acquired company contributes.

Approximately 42%45% of our hourly employees are not unionized. Under the current U.S. presidential administration, certain administrative and regulatory actions have been taken and are being considered that could create more flexibility and opportunity for labor unions to organize non-union workers and could result in a greater percentage of our workforce being subject to collective bargaining agreements, heightening the risks described above. In addition, certain of our customers require or prefer a non-union workforce, and they may reduce the amount of work assigned to us if our non-union labor crews were to become unionized, which could negatively affect our business, financial condition, results of operations financial condition orand cash flows.

We may incur liabilities or suffer negative financial or reputational impacts relating to occupational health and safety matters.

Our operations are subject to extensive laws and regulations relating to the maintenance of safe conditions in the workplace. While we have invested, and will continue to invest, substantial resources in our occupational health and safety programs, our industry involves a high degree of operational risk and there can be no assurance that we will avoid significant liability exposure. Although we have taken what we believe are appropriate precautions, we have suffered fatalities in the past and may suffer additional fatalities in the future. Serious accidents, including fatalities, may subject us to substantial penalties, civil litigation or criminal prosecution. Claims for damages to persons, including claims for bodily injury or loss of life, could result in substantial costs and liabilities, which could materially and adversely affect our results of operations, financial condition or cash flows.liabilities. In addition, if our safety record were to substantially deteriorate over time or we were to suffer substantial penalties or criminal prosecution for violation of health and safety regulations, our customers could cancel our contracts and elect to procure future services from other providers. Unsafe work sites also have the potential to increase employee turnover, increase the costs of projects for our clients, and raise our operating costs. Any of the foregoing could result in financial loss, which could have a material adverse impact on our business, financial condition, results of operations and cash flows.

Risks associated with operating in international markets could restrict our ability to expand globally and harm our business and prospects.

OurAlthough our international operations are presently conducted primarily in Canada and Australia, but we have performedalso perform work in various other foreign countries and we expect that the number of countries in which we operate and the amount of work we perform in foreign countries could expand significantlyincrease over the next few years. Economic conditions, including those resulting from wars, civil unrest, acts of terrorism and other conflicts or volatility in the global markets, may adversely affect our customers, their demand for our services and their ability to pay for our services. In addition, our international operations include business and transactions for which we are paid in local currency. Payments to us in currencies other than the U.S. dollar may exceed our local currency needs, leading to the accumulation of excess local currency, which, in certain instances, may be subject to either temporary blocking, costly taxes or tariffs, or other difficulties convertingif we attempt to convert those amounts to U.S. dollars.

There are also numerous other risks inherent in conducting our business internationally, including, but not limited to, potential instability in international markets, changes in applicable regulatory requirements, applicable to international operations,foreign currency fluctuations, in foreign countries, political, economic and social conditions in foreign countries and complex U.S. and

foreign tax regulations and other laws and treaties, including tax laws.international treaties. These risks could restrict our ability to provide services to international customers, operate our international business profitably or fund our strategic objectives, and our overall business, liquidity andfinancial condition, results of operations and cash flows could be negatively impacted by our foreign activities.

We could be adversely affected by our failure to comply with the laws applicable to our foreign activities, including the U.S. Foreign Corrupt Practices Act and other similar worldwide anti-bribery laws.

The U.S. Foreign Corrupt Practices Act (FCPA) and similar anti-bribery laws in other jurisdictions prohibit U.S.-based companies and their intermediaries from making improper payments to non-U.S. officials for the purpose of obtaining or retaining business. We pursue opportunities in certain parts of the world that experience government corruption, and in certain circumstances, compliance with anti-bribery laws may conflict with local customs and practices. Our policies mandate compliance with all applicable anti-bribery laws. Further, we require our partners, subcontractors, agents and others who work for us or on our behalf to comply with the FCPA and other anti-bribery laws. Although we have policies and procedures designed to ensure that we, our employees, our agents and others who work with us in foreign countries comply with the FCPA and other anti-bribery laws, there is no assurance that such policies or procedures will protect us against liability under the FCPA or other laws for actions taken by our agents, employees and intermediaries. On March 10, 2014, the SEC notified us of an inquiry into certain aspects of our activities in certain foreign jurisdictions and requested that we take necessary steps to preserve and retain categories of relevant documents, including those pertaining to our FCPA compliance program. The SEC has not alleged any violations of law by Quanta or our employees. If we are found to be liable for FCPA violations (either due to our own acts or inadvertence, or due to the acts or inadvertence of others), we could suffer frombe subject to severe criminal or civil penalties or other sanctions, which could have a material adverse effect on our reputation, business, financial condition, results of operations, financial condition orand cash flows. In addition, detecting, investigating and resolving actual or alleged FCPA violations is expensive and could consume significant time and attention of our senior management.

Our participation in joint ventures exposes us to liability and/or harm to our reputation for failures of our partners.

As part of our business, we have entered into joint venture arrangements and may enter into additional joint venture arrangements in the future. The purpose of these joint ventures is typically to combine skills and resources to allow for the performance of particular projects. Success on these jointly performed projects depends in large part on whether our joint venture partners satisfy their contractual obligations. We and our joint venture partners are generally jointly and severally liable for all liabilities and obligations of our joint ventures. If a joint venture partner fails to perform or is financially unable to bear its portion of required capital contributions or other obligations, including liabilities stemming from claims or lawsuits, we could be required to make additional investments, provide additional services or pay more than our proportionate share of a liability to make up for our partner’s shortfall. Further, if we are unable to adequately address our partner’s performance issues, the customer may terminate the project, which could result in legal liability to us, harm our reputation and reduce our profit on a project.

We are in the process of implementing an information technology (IT) solution,solutions, which could temporarily disrupt day-to-day operations at certain operating units.

We continue to implement a comprehensive IT solutionsolutions that we believe will allow for the interface between functions such as accounting and finance, human resources, operations, and fleet management. Continued development and implementation of the IT solutionsolutions will require substantial financial and personnel resources. While the IT solution issolutions are intended to improve and enhance our information systems, implementation of new information systems at each operating unit exposes us to the risks of start-up of the new system and integration of that system with our existing systems and processes, including possible disruption of our financial reporting. There is no guarantee that we will realize economic or other intended benefits from continued development and

implementation of the IT solution.solutions. Additionally, the IT solutionsolutions may not be developed or implemented as timely or as accurately as planned. Failure to properly implement the IT solutionsolutions could result in substantial disruptions to our business, including coordinating and processing our normal business activities, testing and recording of certain data necessary to provide oversight over our disclosure controls and procedures and effective internal controls over our financial reporting, and other unforeseen problems.

FailureOur failure to adequately protect critical data and technology systems could materially affect our operations.business, financial condition, results of operations and cash flows.

We rely heavily on computer, information, and communications technology and related systems to manage our operations and other business processes and to protect sensitive information maintained in the normal course of business. Cyber-attacks and physical security risks, such as storms or other natural phenomena, along with IT solution failures, network disruptions and other breaches of data security, could disrupt our operations by causing, among other things, delays or cancellation of customer orders, impedingin the processing of transactions andor the reporting of financial results resulting inor the unintentional disclosure of customer, employee or company information (including confidential or proprietary information) that could damage our reputation.

Additionally, cyber-attacks or acts of terrorism against us, our customers and/or our information,vendors or other breaches of our data security could cause service disruption or loss of control of our customers’ energy infrastructure systems, which could subject us to significant liabilities and cause damage to our reputation.

While management has taken steps to address these concerns by implementing network security and internal control measures, there can be no assurance that a system failure or data security breach (particularly in light of our ongoing implementation of the IT solution)above events will not occur, and such events could have a material adverse effect on our business, financial condition, results of operations and operating results.cash flows.

Our dependence on suppliers, subcontractors and equipment manufacturers could expose us to the risk of loss in our operations.

On certain projects, we rely on suppliers to obtain the necessary materials and subcontractors to perform portions of our services. We also rely on equipment manufacturers to provide us with the equipment required to conduct our operations. Although we are not dependent on any single supplier, subcontractor or equipment manufacturer, any substantial limitation on the availability of required suppliers, subcontractors or equipment manufacturers could negatively impact our operations. The risk of a lack of available suppliers, subcontractors or equipment manufacturers may be heightened as a result of market and economic conditions. To the extent we cannot engage subcontractors or acquire equipment or materials, weour operations could experience losses in the performancebe negatively impacted. Additionally, successful completion of our operations.contracts may depend on whether our subcontractors successfully fulfill their contractual obligations. If our subcontractors fail to perform their contractual obligations as a result of financial or other difficulties, or if our subcontractors fail to meet the expected completion dates or quality standards, we may be required to incur additional costs or provide additional services in order to make up such shortfall.

We may not have access in the future to sufficient funding to finance desired growth and operations.

If we cannot secure future funds or financing on acceptable terms, we may be unable to support our future operations or growth strategy or future operations.strategy. We cannot readily predict the ability of certain customers to pay for past services, and unfavorable economic conditions, such as those experienced over recent years, may negatively impact the ability of our customers to pay amounts owed to us. We may also use cash for acquisitions as well as forand other investments, both of which are elements of our growth strategy, but we cannot readily predictand the timing size and successsize of our acquisition or investment efforts. Using cash for acquisitionsefforts cannot be readily predicted. Acquisitions and investments limitsfunded by cash on hand, cash from operations and cash from our current credit facility limit our financial flexibility and may increase our need to seek additional capital through futureadditional debt or equity financings. Our existing credit facility contains significant restrictions on our operational and financial flexibility, including our ability to incur additional debt or conduct certain types of preferred equity financings, and if we seek more debt, we may have to agree to additional covenants that limit our operational and financial flexibility. If we seek additional debt or equity financings, we cannot be certain that additional debt or equity will be available to us on terms acceptable to us or at all. Furthermore, our credit facility is based upon existing commitments from several banks. Banks have become more restrictive in their lending practices following the difficulties in the credit markets, and some may be unable or unwilling to fund their commitments, which may limit our access to the

capital needed to fund our growth and operations. In addition, weWe also rely on financing companies to fund the leasing of certain of our trucks and trailers, support vehicles and specialty construction equipment. Credit market conditions may cause certain of these financing companies to restrict or withhold access to capital for us to fund the leasing of additional equipment. Although we are not dependent on any single equipment lessor, a widespread lack of available capital to fund the leasing of equipment could negatively impact our future operations.

Our credit agreement contains significant restrictions, including financial covenants and other restrictions on our ability to borrow amounts under the agreement and limitations on our ability to incur additional debt or conduct certain types of preferred equity financings. Our ability to increase the current commitments under our credit facility is also dependent upon additional commitments from our lenders. Furthermore, if we are permitted under our credit facility to seek additional debt or equity financings, we cannot be certain they will be available to us on acceptable terms or at all, as banks are often restrictive in their lending practices, and additional debt financing may include covenants that further limit our operational and financial flexibility. If we are unable to borrow under our current credit agreement or secure other financing or if our lenders become unable or unwilling to fund their commitments to us, we may not be able to access the capital needed to fund our growth and operations. For additional information on the terms of our credit facility, please read Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations — Debt Instruments — Credit Facility.

Additionally, the market price of our common stock may change significantly in response to various factors and events beyond our control, which will impact our ability to use equity to obtain funds. A variety of events may cause the market price of our common stock to fluctuate significantly, including overall market conditions or volatility, a shortfall in our operating results from those anticipated, negative results or other unfavorable information relating to our market peers or the other risks described in this Annual Report on Form 10-K.

Fluctuating foreign currency exchange rates may have a greater impact on our financial results as we expand into international markets.

For the year ended December 31, 2013,2015, we derived $1.31$1.54 billion, or 20.1%20.4%, of our consolidated revenues from foreign operations, the substantial majority of which was earned in Canada and Australia. The functional currencies for our foreign operations are typically the currency of the country in which the foreign operating unit is located. Accordingly, our financial performance is subject to fluctuation due to changes in foreign currency exchange rates relative to the U.S. dollar. As the U.S. dollar strengthens against foreign currencies, our translation of foreign currency denominated revenues or expenses will result in lower U.S. dollar denominated revenues and expenses. Conversely, if the U.S. dollar weakens against foreign currencies, the translation of these foreign currency denominated revenues or expenses will result in increased U.S. dollar denominated revenues and expenses. For example, during the year ended December 31, 2015, foreign revenues decreased by approximately $227 million in comparison with the year ended December 31, 2014 as a result of less favorable foreign currency exchange rates due to the U.S. dollar strengthening against the Canadian and Australian dollars.

We intend to expand the volume of services that we provide internationally. As a result, our reported financial condition, and results of operations and cash flows may be further exposed to the effects that fluctuating exchange rates have on the process of translating the financial statements of our international operations and the remeasurement of transactions which are usuallynot denominated in local currencies, into the U.S. dollar.reporting units’ functional currencies.

Our business growth could outpace the capability of our decentralized management infrastructure.

We cannot be certain that our management infrastructure will be adequate to support our operations as they expand. For example, the ability to internally communicate, coordinate and execute business strategies, plans and tactics may be negatively impacted by our increasing size and complexity. A decentralized structure places significant control and decision-making powers in the hands of localour operating unit management. This contributes to the risk that we may be slower or less able to identify or react to problems affecting key business matters than we would in a more centralized environment. The lack of timely access to information may impact the quality of decision making by management. Our decentralized organization creates the possibility that our operating subsidiaries assume excessive risk without appropriate guidance from our centralized legal, accounting, tax, treasury and insurance functions as to the potential overall impact. Future growth could also could impose significant additional responsibilities on members of our senior management, including the need to recruit and integrate new senior level managers and executives. We cannot be certain that we will be able to recruit and retain such

additional managers and executives. To the extent that we are unable to manage our growth effectively, or are unable to attract and retain additional qualified management, we may not be able to expand our operations or execute our business plan.

We may be unable to compete for or work on certain projects if we are not able to obtain surety bonds.bonds, letters of credit or bank guarantees.

A portion of our business depends on our ability to provide surety bonds, letters of credit, bank guarantees or other financial assurances. Current or future market conditions, including losses incurred in the construction industry or as a result of large corporate bankruptcies, as well as changes in our sureties’ assessment of our operating and financial risk, could cause our surety providers and lenders to decline to issue or renew, or substantially reduce the amount of, bid and/or performance bonds for our work and could increase our bonding costs.costs associated with collateral. These actions could be taken on short notice. If our surety providers or lenders were to limit or eliminate our access to bonding, letters of credit or guarantees, our alternatives would include seeking bonding capacity from other sureties and lenders or finding more business that does not require bonds or postingthat allows for other forms of collateral for project performance, such as letters of credit or cash. We may be unable to secure these alternatives in a timely manner, on acceptable terms, or at all, which could affect our ability to bid for or work on future projects requiring financial assurances.

We have also granted security interests in various of ourcertain assets to collateralize our obligations to our sureties.sureties and lenders. Furthermore, under standard terms in the surety market, sureties issue or continue bonds on a project-

by-projectproject-by-project basis and can decline to issue bonds at any time or require the posting of additional collateral as a condition to issuing or renewing any bonds. If we were to experience an interruption or reduction in the availability of bonding capacity as a result of these or any other reasons, we may be unable to compete for or work on certain projects that would require bonding.

Our failure to comply with environmental laws could result in significant liabilities.

Our operations are subject to various environmental laws and regulations, including those dealing with the handling and disposal of waste products, PCBs, fuel storage and air quality. We perform work in many different types of underground environments. If the field location maps supplied to us are not accurate, or if objects are present in the soil that are not indicated on the field location maps, our underground work could strike objects in the soil, some of which may contain pollutants. These objects may also rupture, resulting in the discharge of pollutants. In such circumstances, we may be liable for fines and damages, and we may be unable to obtain reimbursement from the parties providing the incorrect information. We perform work in and around environmentally sensitive areas such as rivers, lakes and wetlands. In addition, we perform directional drilling operations below certain environmentally sensitive terrains and water bodies. Due to the inconsistent nature of the terrain and water bodies, it is possible that such directional drilling may cause a surface fracture, resulting in the release of subsurface materials. These subsurface materials may contain contaminants in excess of amounts permitted by law, potentially exposing us to remediation costs and fines. We also own and lease several facilities at which we store our equipment. Some of these facilities contain fuel storage tanks that are above or below ground. If these tanks were to leak, we could be responsible for the cost of remediation as well as potential fines.

In addition, new laws and regulations, stricter enforcement of existing laws and regulations, the discovery of previously unknown contamination or leaks, or the imposition of new clean-up requirements could require us to incur significant costs or become the basis for new or increased liabilities that could negatively impact our business, financial condition, results of operations orand cash flows. In certain instances, we have obtained indemnification or covenants from third parties (including predecessors or lessors) for such clean-up and other obligations and liabilities that we believe are adequate to cover such obligations and liabilities. However, such third-party indemnities or covenants may not cover all of our costs and the indemnitors may not pay amounts owed to us, and such unanticipated obligations or liabilities, or future obligations and liabilities, may have a material adverse effect on our business, financial condition, results of operations financial condition orand cash flows. Further, we cannot be certain that we will be able to identify or be indemnified for all potential environmental liabilities relating to any acquired business.

There are also other legislative and regulatory proposals to address greenhouse gas emissions. These proposals, if enacted, could result in a variety of regulatory programs including potential new regulations, additional charges to fund energy efficiency activities, or other regulatory actions. Any of these actions could result in increased costs associated with our operations and impact the prices we charge our customers. For example, if new regulations are adopted regulating greenhouse gas emissions from mobile sources such as cars and trucks, we could experience a significant increase in environmental compliance costs in light of our large rolling-stock fleet. In addition, if our operations are perceived to result in high greenhouse gas emissions, our reputation could suffer.

We may not be successful in continuing to meet the requirements of the Sarbanes-Oxley Act of 2002.

The Sarbanes-Oxley Act of 2002 has many requirements applicable to us regarding corporate governance and financial reporting, including the requirements for management to report on our internal controls over financial reporting and for our independent registered public accounting firm to express an opinion overon the operating effectiveness of our internal control over financial reporting. During 2013,2015, we continued actions to ensure our ability to comply with these requirements. As of December 31, 2013,2015, our internal control over financial reporting was effective; however, there can be no assurance that our internal control over financial reporting will be effective in future years. Failure to maintain effective internal controls or the identification ofto identify significant internal control deficiencies in acquired companies (both prior acquisitions already made or made in theand future acquisitions) could result in a

decrease in the market value of our common stock and our other publicly traded securities, thea reduced ability to obtain debt and equity financing, thea loss of customers, or penalties and additional expenditures to meet the requirements.

If we are unable to enforce our intellectual property rights or if our intellectual property rights become obsolete, our competitive position could be adversely impacted.

We utilize a variety of intellectual property rights inwhile performing our services. We view our portfolio of proprietary energized services tools and techniques as well as ourand other process and design technologies as one of our competitive strengths, which we believe differentiatesdifferentiate our service offerings. We may not be able to successfully preserve these intellectual property rights in the future, and these rights could be invalidated, circumvented or challenged. In addition, the laws of some foreign countries in which our services may be sold do not protect intellectual property rights to the same extent as the laws of the United States. We also license certain technologies from third parties, and there is a risk that our relationships with licensors may terminate or expire or may be interrupted or harmed. If we are unable to protect and maintain our intellectual property rights, or if intellectual property challenges or infringement proceedings succeed against us, our ability to differentiate our service offerings could be reduced. In addition, if our intellectual property rights or work processes become obsolete, we may not be able to differentiate our service offerings, and some of our competitors may be able to offer more attractive services to our customers. As a result, our business and revenuerevenues could be materially and adversely affected.

We may incur additional healthcare costs arising from federal healthcare reform legislation.

In March 2010, the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010 (the(collectively ACA) were signed into law in the U.S. TheUnited States. ACA is intended to expand access to health insurance coverage to many uninsured individuals and expands coverage to those already insured. The changes and mandates on employers subject to the ACA’s “pay or play” requirements could cause us to incur additional group health insurance costs, although we do not expect any material short-term impact on our financial results as a result of the ACA. We continue to monitor developments under the ACA and assess the extent to which it could result in long-term material cost increases for us.

Opportunities within the government arena could subject us to increased governmental regulation and costs.

Most government contracts are awarded through a regulated competitive bidding process. As we pursue increased opportunities in the government arena, management’s focus associated with the start-up and bidding

process may be diverted away from other opportunities. Involvement with government contracts could require a significant amount of costs to be incurred before any revenues are realized from these contracts. In addition, as a government contractor, we are subject to a number of procurement rules and other public sector regulations, any deemed violation of which could lead to fines or penalties or a loss of business. Government agencies routinely audit and investigate government contractors. Government agencies may review a contractor’s performance under its contracts, cost structure and compliance with applicable laws, regulations and standards. If a government agency determines that costs were improperly allocated to specific contracts, such costs will not be reimbursed or a refund of previously reimbursed costs may be required. If a government agency alleges or proves improper activity, civil and criminal penalties could be imposed and serious reputational harm could result. Many government contracts must be appropriated each year. If appropriations are not made in subsequent years, we would not realize all of the potential revenues from any awarded contracts.

Our sale or issuance of additional common stock or other equity-related securities could dilute each stockholder’s ownership interest or adversely affect the market price of our common stock.

We grow our business organically as well as through acquisitions. We often fund all or a portion of the consideration paid in connection with our acquisitions with the issuance of additional equity securities, including shares of our common stock and securities that are convertible into shares of our common stock.

We may issue additional equity securities in the future, including in connection with future acquisitions or other issuances of our common stock or convertible securities or otherwise. Our Restated Certificate of Incorporation provides that we may issue up to 600,000,000 shares of common stock, of which 152,907,166 shares were outstanding as of December 31, 2015. Additionally, former owners of acquired companies own exchangeable shares, 6,876,042 of which were outstanding as of December 31, 2015 and included in the calculation of basic and diluted weighted average shares outstanding. These shares are exchangeable for shares of Quanta common stock on a one-for-one basis. Any additional issuances of common stock or exchangeable shares could have the effect of diluting our earnings per share and our existing stockholders’ individual ownership percentages and could lead to volatility in the market price of our common stock. We cannot predict the effect that future issuances of our common stock or other equity-related securities would have on the market price of our common stock.

Certain provisions of our corporate governing documents could make an acquisition of our company more difficult.

The following provisions of our certificate of incorporation and bylaws,charter documents, as currently in effect, as well asand Delaware law could discourage potential proposals to acquire us, delay or prevent a change in control of us or limit the price that investors may be willing to pay in the future for shares of our common stock:

None.

Facilities

We lease our corporate headquarters in Houston, Texas and maintain other facilities throughout North America and in various foreign locations where we conduct business. Our facilities are used for offices, equipment yards, warehouses, storage and vehicle shops. As of December 31, 2013,2015, we owned 3748 of the facilities we occupy, many of which are encumbered by a security interest granted under our credit facility,agreement, and we leased the remainder. We believe that our existing facilities are sufficient for our current needs.

Equipment

We operate a fleet of owned and leased trucks and trailers, support vehicles and specialty construction equipment, such as backhoes, excavators, trenchers, generators, boring machines, cranes, robotic arms, wire pullers, tensioners, marine vessels and helicopters. Our owned equipment and the leasehold interestinterests in our leased equipment are encumbered by a security interest granted under our credit facility.agreement. As of December 31, 2013,2015, the total size of the rolling-stock fleet was approximately 27,00036,778 units. Most of our fleet is serviced by our own mechanics who work at various maintenance sites and facilities. We believe that our equipment is generally well maintained and adequate for our present operations.

We are from time to time party to various lawsuits, claims and other legal proceedings that arise in the ordinary course of business. These actions typically seek, among other things, compensation for alleged personal injury, breach of contract and/or property damages, employment-related damages, punitive damages, civil penalties or other losses, or injunctive or declaratory relief. With respect to all such lawsuits, claims and proceedings, we record a reserve when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. In addition, we disclose matters for which management believes a material loss is at least reasonably possible. SeeLitigationLegal Proceedings and ClaimsCollective Bargaining Agreements in Note 15 of the Notes to Consolidated Financial Statements in Item 8.“Financial Statements and Supplementary Data”Data,, which isare incorporated by reference in this Item 3, for additional information regarding litigation, claims and other legal proceedings.

Not applicable.

PART II

Our common stock is listed on the New York Stock Exchange (NYSE) under the symbol “PWR.” The following table sets forth the high and low sales prices of our common stock per quarter, as reported by the NYSE, for the two most recent fiscal years.

On February 21, 2014,23, 2016, there were 849756 holders of record of our common stock, two16 holders of record of exchangeable shares of Canadian subsidiaries of Quanta, one holder of record of our Series F preferred stock and one holder of record of our Series G preferred stock. There is no established trading market for the exchangeable shares or the Series F and Series G preferred stock; however, the exchangeable shares may be exchanged at the option of the holder for Quanta common stock on a one-for-one basis. See NotesNote 11 and 18 of the Notes to Consolidated Financial Statements in Item 8.“Financial Statements and Supplementary Data”Data for additional discussion of our equity securities.

Unregistered Sales of Securities During the Fourth Quarter of 20132015

During the fourth quarter of 2013, we completed three acquisitions in which a portion of the consideration consisted of the unregistered issuance of shares of our common stock. Aggregate consideration consisted of approximately $175.8 million in cash and 2,747,412 shares of our common stock. Such shares of common stock were issued in reliance upon the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended, as the shares were issued to the owners of the businesses acquired in privately negotiated transactions not involving any public offering or solicitation.None.

Issuer Purchases of Equity Securities During the Fourth Quarter of 20132015

The following table contains information about our purchases of equity securities during the three months ended December 31, 2013.2015.